2017
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Engineered, Built and Supported in the U.S.A.
General Public Address
and Intercom System
Design Guidelines
REV 2017-1.19
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© 2016-2017 Valcom, Inc. Roanoke, VA
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Founded in 1977, Valcom is the largest manufacturer of integrated public
address systems in the world and is the product of choice for thousands of
integrators and their customers worldwide. Our products are marketed
through established, local direct distributors and integrators. Valcom offers a
wide variety of products providing the best public address/intercom systems
and emergency mass notification solutions for manufacturing/warehouse
facilities, schools, universities, airports, hospitals and for your facility as well.
Valcom has long capitalized on the many advantages of using low voltage
cabling and distributed amplification. Both our Self Amplified One Way
analog and VoIP IP based systems offer distinct advantages over previous
technologies.
Virtually all of our products are proudly manufactured in our state of the art
facilities in Roanoke, Virginia, USA. Valcom’s Engineered Systems Division
specializes in large, sophisticated school intercom, and scalable Emergency
Mass Notification Solutions. Our clients include major universities,
government entities, medical and transportation facilities.
Our product offering is extremely comprehensive. We have regional product
experts available. They are eager to discuss a solution tailored to your
specific mass communication or school intercom requirements. We
encourage you to contact us today.
In addition to this document, we encourage you to review our Best Practices
and General Troubleshooting Procedures guide.
We strongly encourage you to check for document updates often by
following the update link found in the footer.
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Table of Contents
INTRODUCTION .................................................................................................................................5
REQUESTS FOR PROPOSAL (RFPS) .....................................................................................................................................6
CONDUCT A SITE SURVEY ................................................................................................................................................7
DEFINE THE SCOPE OF WORK ...........................................................................................................................................7
GETTING STARTED .............................................................................................................................8
TECHNOLOGY CHOICES ...................................................................................................................................................8
FULL IP INTERCOM .........................................................................................................................................................9
SPEAKER CHOICES ........................................................................................................................................................12
Special Application Speakers/Horns ...................................................................................................................14
High Fidelity Speakers ........................................................................................................................................14
DESIGN BY LOCATION ...................................................................................................................................................14
DETERMINING ZONING .................................................................................................................................................14
PLAN CABLING TO SUPPORT ZONING/GRANULARITY ...........................................................................................................15
SYSTEM POWER...........................................................................................................................................................15
FEEDBACK ELIMINATION ................................................................................................................................................15
VALCOM SELF AMPLIFIED SPEAKER WIRE LENGTH ..............................................................................................................16
PLAN SYSTEM ACCESS ...................................................................................................................................................19
MICROPHONE VS. TELEPHONE ACCESS .............................................................................................................................20
TELEPHONE SPEAKER UTILIZATION ..................................................................................................................................21
TYPICAL SYSTEM FEATURES ............................................................................................................................................21
CLOCK CHOICES ...........................................................................................................................................................22
SPEAKER AND CLOCK ACCESSORIES AND ENHANCEMENTS ....................................................................................................25
VISUAL PAGING ...........................................................................................................................................................26
RETROFIT SYSTEMS ......................................................................................................................................................26
REUSING EXISTING EQUIPMENT ......................................................................................................................................27
INTEGRATING WITH NON-VALCOM EQUIPMENT .................................................................................................................28
PUTTING IT ALL TOGETHER ............................................................................................................................................28
BASIC PRE-CALL CHECKLIST............................................................................................................................................29
SYSTEM DESIGN SOFTWARE ............................................................................................................. 30
COMMON VERTICAL MARKET FEATURES .......................................................................................... 31
K-12 SCHOOLS ............................................................................................................................................................32
K-12 Specific Design Questionnaire ....................................................................................................................33
K-12 Specific Design Document ..........................................................................................................................33
HIGHER EDUCATION .....................................................................................................................................................34
GOVERNMENT/MILITARY ..............................................................................................................................................35
COMMERCIAL/INDUSTRIAL ............................................................................................................................................36
HEALTHCARE ...............................................................................................................................................................37
TRANSPORTATION ........................................................................................................................................................38
NEED MORE IDEAS?......................................................................................................................................................38
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GLOSSARY OF INDUSTRY TERMS....................................................................................................... 39
LET’S NOT MAKE ASSUMPTIONS....................................................................................................... 56
DISCLAIMER ..................................................................................................................................... 63
WE’D LIKE TO HEAR FROM YOU!....................................................................................................... 63
When specifying authorities base designs upon old specs, they perpetuate old solutions.
When specifying authorities are more interested in meeting or exceeding the needs of a
facility than specifying the exact equipment to do so, we can offer the best solution 99%
of the time.
Select the speaker and clock types and quantities for each area, select the desired
access method and features - then let us provide an amazing solution!
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Introduction
Public address systems became increasingly popular throughout the 20th century. The
industrial revolution led to large scale manufacturing facilities with hundreds, if not
thousands, of employees. Maintaining efficiency of such large scale operations required
the ability to locate key individuals rapidly and communicate to the masses
instantaneously. The only logical solution was a facility wide speaker system.
From those early roots has grown an industry dedicated to internal communications.
Systems have evolved from the old fashioned centrally amplified, microphone actuated
public address systems, to multimodal telephone based systems that utilize integrated
circuits, microprocessors and data network connectivity.
Today’s internal communication systems are comprised of both primary and secondary
communication devices. Primary devices provide instantaneous communication that
requires no action on the part or the message recipients. Even today, primary alerting is
best accomplished with a facility wide speaker system.
Secondary communication devices require the user to take some action or to be prepared
to receive the message. Examples include social media, text messaging and e-mail.
Today, both primary and secondary communication systems can work in tandem.
Modern public address systems are designed not only for general announcements, but
for emergency notification. They often feature both one-way and two-way communication
and supervision to insure their availability in crisis situations.
Under microprocessor control, modern public address systems allow users to dynamically
choose message destinations and feature both live voice and prerecorded audio
capabilities.
Modern public address systems save money and lives.
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Requests for Proposal (RFPs)
We will be pleased to review any published RFQs or RFPs associated with your
opportunities, however, it’s rare that these documents provide the device types and
counts required to provide a quote.
RFPs and RFQs are often crafted from bid specifications provided by manufacturers and
written around specific products. Manufacturers write their bid specifications in such a
way that only their products may be considered. These documents often require rarely,
or never used features and functions that are specific to one manufacturer.
Occasionally, RFPs and RFQs actually represent products on which an end user has
standardized. These often disallow substitution and may, if reissued without the benefit
of oversight, perpetuate the use of old technologies.
Too often, however, RFPs and RFQs are fabricated using cut and paste from various
manufacturers’ bid specifications and cannot be met line-by-line by anyone.
Many times, strict adherence to RFPs and RFQs can limit an End User’s options in
obtaining superior state-of-the-art solutions offering all of the features that they really
need.
In most cases, what’s truly important is meeting or exceeding the intent of the
specification.
We still see newly published RFPs and RFQs that were written in the 1950s. If no one
had ever worked to modernize these, we’d all be using rotary telephones, switch bank
manual intercoms and old fashioned central amplifiers.
Remember that RFPs simply indicate a need and are a starting point towards obtaining
the best solution to satisfy that need. Providing this solution is the best service that we
can provide to the End User.
Superior results are realized when you work proactively with specifying authorities and
End Users to educate them on the best solutions available. If your company simply
responds to published RFPs and RFQs, and those RFPs specify dated technology, then
we will offer a better solution using our innovative products. It is our task, together, to
work with specifying authorities to teach them why Valcom solutions are better. We have
a great deal of marketing collateral to support this fact and we will gladly participate in
webinars, conference calls, and, when practical, live demonstrations to decision makers.
We offer great solutions; therefore, we have had great success with this strategy.
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As a manufacturer, our quotes are based upon customer provided material lists. If you
provide the information required to do so, we can assist in product selection.
Remember that the solution that we suggest can only be as accurate as the
information that you provide.
This document will guide you to providing the information that we need to provide a
complete and accurate equipment list for your application.
Conduct a Site Survey
Whenever possible, conduct an on-site survey of the intended jobsite. An ideal time to
visit is when the site is in full operation so that you can gather accurate noise level and
activity data from the site.
Site surveys can provide important details that RFPs alone cannot. RFPs don’t typically
advise of costly accessibility challenges like asbestos laden ceilings, heavy room
furnishings that must be moved to complete work, requiring a rented scissor lift to mount
horns, or concrete walls through which infrastructure must be routed. While on-site,
document the locations of available, dedicated ac power outlets and facility network
switches. Also note where additional network access and ac power will be required.
We’ve prepared a Site Survey Form to assist you in your site survey. It is available in both
Microsoft Word and PDF formats.
Define the Scope of Work
After you conduct the site survey, an important part of a project’s initial bid process is for
you and your client to formally document a detailed scope of work. Unstated customer
expectations can quickly lead to dissatisfaction and expensive cost overruns. Detail the
customer’s expectations and where your responsibility begins and ends. Don’t firmly
commit to reusing any existing infrastructure or equipment without a caveat of “if
compatible and in good condition”. Agree to a process of change orders should the
customer expand their expectations or if site conditions are not as described in the scope
and warrant additional charges.
Site access is closely related to defining the scope of work. Agree upon times when the
contracted work can be performed. Oftentimes, the best time to work is after a site’s
regular business hours, however, work related areas may be locked at these times. Prenegotiate unrestricted access to all areas involved in the scope. Having your technicians
wait for a security guard or custodian to open a locked room is never a profitable situation.
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Getting Started
Technology Choices
Before integrated circuit technology, all speaker systems used old fashioned central
amplifiers and heavy gauge shielded wire. While old fashioned central amplifiers are still
used today, a more common approach allows the use of small gauge UTP and selfamplified or IP based technology.
Self-amplified or IP based technologies allow for easy installation, functional versatility,
large scale deployment, and remote maintenance. UTP based systems are always the
best choice for large, busy facilities since they inherently support many simultaneous
announcements and/or talkback intercom conversations.
Old fashioned centrally amplified systems are restricted to one broadcast per central
amplifier at any given time.
Self-amplified speakers feature a non-blocking, independently volume controlled,
matched amplifier per speaker. They connect to the audio source and a shared dc power
supply using UTP cabling.
IP speakers communicate over a properly configured network and offer all the benefits of
self-amplified technology plus more.
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IP speakers connect, and are powered via PoE network switch ports (one per IP speaker),
are independently addressable and feature virtual software based volume adjustment and
programming. IP speaker systems easily span multiple buildings, cities, states and
countries.
Full IP Intercom
Valcom IP Mass Notification/Intercom systems differ from analog wired systems in
numerous ways.
Hosting facility systems on a LAN/WAN provides many benefits, not the least of which long term cost savings. Managing multiple IP based systems typically requires fewer
personnel due to the fact that most adjustments and diagnostics may be performed
remotely. That means less time lost driving to sites, fewer service vehicles required, less
vehicle insurance cost, less fuel cost, and more multitasking.
Unlike analog systems, Valcom IP Mass Notification/Intercom systems do not require a
central control system. They are hosted on the LAN/WAN, therefore the physical location
of endpoints and their proximity to each other is irrelevant. Also unlike analog systems,
system size constraints are essentially non-existent. These systems are easily deployed
on a facility, enterprise and/or global scale.
Valcom’s server-less design means that if properly configured network connectivity exists
between endpoints, they will be able to communicate. This robust, redundant strategy
coupled with inherent supervision, explains why Valcom IP Mass Notification/Intercom
systems are utilized in some of the most vital facilities in the world.
A full complement of one way or intercom PoE speakers and horns are available to suit
any area. These speakers and horns connect as network endpoints and may be selected
in any combination conceivable for announcements to a single area, multiple areas, or
everywhere. Access may be via single line POTS type telephones, FXO ports, loop start
C.O. line ports, loop start trunk ports, SIP, microphone or analog station ports (FXS)
featuring CPD (Calling Party Disconnect).
Visual notification devices, such as LED displays, may easily be incorporated into your
design to deliver messages to high noise areas, to benefit hearing impaired individuals,
or anywhere that visual alerting is desired.
Retrofit Gateways are available in 8 channel models. They are intended for upgrading
existing analog intercoms. Each channel provides an adjustable talkback audio feed to
either one 45-ohm (VE8045) or one old fashioned 25-volt (VE8025) intercom speaker.
Two of these channels are dual mode and feature a parallel line level output for direct
connection to an amplifier line level input or to self-amplified speakers. Additionally, one
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normally open call button input is available per channel. An auxiliary input is provided for
local program material.
Input/Output Gateways allow users to launch messages from panic buttons or
automatically from 3rd party monitoring devices. They also provide switch outputs to
control electric door locks, lighting or any other facility system.
Audio gateways allow the introduction of music, microphone or other external audio
sources. They may also provide audio outputs to facilitate integration of existing legacy
analog paging systems, radio systems, etc.
Although the Valcom IP Mass Notification/Intercom systems feature a server-less design,
there are Application servers available to provide desirable features.
Telephone Paging Servers allow the broadcast of system announcements through the
speakers of many existing IP telephones. This simple addition adds audio coverage to
private offices and other areas that may not be close to a system speaker.
Application Servers may be added to provide scheduled tones, music, prerecorded or live
announcements. They also provide a graphical browser interface to launch messages or
monitor call status. Application servers feature the ability to monitor data feeds such as
syslog, RSS, ATOM or CAP feeds to automatically launch one or more messages to
speakers/horns, IP telephone speakers, text to LED signs, as well as screen pop ups on
PCs. All the messaging modes may be simultaneously initiated from a single user action.
Advanced Servers allow users to launch their own emergency announcements via CAP,
RSS and/or ATOM feeds. This allows the incorporation of any system capable of
responding to such feeds.
All servers have a high availability option.
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What’s the best solution?
There is no overall best solution. It depends on the requirements of any given site. Both
self-amplified and IP systems are widely deployed and used as a standard worldwide.
While full IP deployment offers the most versatility, it’s not uncommon to use IP gateways
and Application Servers for audio distribution between local wiring closets while using
analog self-amplified or talkback speakers and horns as the actual sound points.
This is all part of the many benefits of Valcom’s technologies. There are typically multiple
options to achieve the end user’s internal communication goals.
The choice of using VoIP or analog equipment for the main control and audio distribution
is dependent upon many factors:
a) The preference of the owner
b) The size of the system
c) The number of sites included in the system
a. If properly configured network connectivity exists between the Valcom IP
gateways and endpoints, they will work together. That’s a very strong
advantage of choosing an IP solution; you can have as many "main" and
"remote" sites as are necessary. Systems installed in different geographical
areas may all act as one. Unless a single site is providing specific services,
losing network connectivity to one site does not affect the others at all. For
this reason, IP is the best choice for large installations.
d) The feature set required
e) Initial budget
f) Desire for long term cost savings
g) Expertise of the installer
h) Expertise of the owner
a. Systems that will be maintained by a facility’s IT department are typically
full IP deployments.
b. Systems maintained by facilities management are typically full IP, analog or
a hybrid of both.
We will gladly assist you in choosing one or more options for your application.
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Speaker Choices
There are many speaker styles available.
Ceiling speakers spaced at no more than twice the mounting height are the best choice
for even sound coverage in interior areas. When following this rule, coverage per speaker
is simply the square of the spacing. For example, with 8 foot ceilings,
maximum spacing between speakers would be 16 feet and each would
cover 162 or 256 square feet. If working in meters, then the units simply
change to meters and meters2. Contact us if the ceilings are over 25
feet (7.6 meters) high or if the ambient noise level is over 76 dBspl.
In critical noisy areas, like airport gate areas, space ceiling speakers at [2 x (mounting
height – 4 feet)]. Or if using meters [2 x (mounting height – 1.2 meters)].
The first and last rows of ceiling speakers should begin at half the spacing distance from
adjacent walls.
Conveniently, our example used a room with perfect dimensions for the desired spacing.
In practice, this rarely happens. If the room dimensions are not ideal for the desired
spacing, simply make adjustments:
Desired spacing = 16 feet (16’)
Actual room dimensions 20’ x 30’
20’ ÷ 16’ = 1.25 speakers/row – round up to 2 speakers/row
30’ ÷ 16’ = 1.87 speakers/column – round up to 2 speakers/column
To determine the new spacing:
20’ ÷ 2 = 10’ spacing between speakers. ½ that distance starting from walls (5’)
30’ ÷ 2 = 15’ spacing between speakers. ½ that distance starting from walls (7.5’)
Wall speakers should only be used in small interior areas where there will only be a single
speaker, or if the use of ceiling speakers is not an option.
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Horns are typically reserved for use in exterior environments, harsh environments or
large, loud interior locations.
As a general rule, horns and speakers providing audio to an area should be installed such
that all sound is projected in the same direction.
Audio coverage by speakers and horns is a function of mounting height and the area’s
ambient acoustic characteristics and noise level. For non-reverberant areas, refer to the
recommended spacing chart below. Note that, for horns, the chart is based upon an 18
foot (5.5 meter) mounting height. Tips for reverberant areas may be found here.
Imperial units of measure
Mounting Height x 2 =
Ceiling Speaker
Placement
Wall Speaker Placement
Spaced 20’ Apart
Horns
Speaker & Horn Placement Guide
(1 per 600 ft2)
Quiet
50-65 dB
110’
(12,000 ft2)
Moderate
65-80 dB
80’
(6,400 ft2)
15 Watt
-
-
30 Watt
-
-
5 Watt
Noisy
80-90 dB
50’
(2,500 ft2)
75’
(5,600 ft2)
-
Very Noisy
90 dB+
30’
(900 ft2)
45’
(2,000 ft2)
60’
(3,600 ft2)
Shows space between horns and coverage per horn
Metric units of measure
Wall Speaker Placement
Spaced 6m Apart
(1 per 56 m²)
Horns
Metric Speaker & Horn Placement Guide
Quiet
Moderate
Noisy
Mounting Height x 2 =
50-65 dB
65-80 dB
80-90 dB
Ceiling Speaker
34 m
25 m
15 m
5 Watt
Placement
(1,115 m²)
(595 m²)
(232 m²)
15 Watt
-
-
23 m
(520 m²)
30 Watt
-
-
-
Very Noisy
90 dB+
9m
(84 m²)
14 m
(186 m²)
18 m
(334 m²)
Shows space between horns and coverage per horn
If your design will include analog speakers or horns mounted in locations that will be
difficult to access after installation, or includes areas with many speakers connected in
parallel, add convenient wall mount volume controls to make future adjustment easier.
Talkback, or 2-way intercom capability, is an option with any style of speaker or horn.
Speakers or horns used as talkback intercom points are typically accompanied by a
separately mounted pushbutton (call button). The button allows users to ring a telephone.
Once the telephone is answered, a bidirectional connection is established with the
talkback intercom point.
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Talkback is an automatically switched, hands free connection and does not require pushto-talk. The talkback conversation is terminated when the telephone terminates the call.
Talkback intercom points are very common in classrooms, hospital operating rooms,
elevators, building entrances, medical examination rooms and car dealership mechanic
bays. Talkback capability works best in quiet areas and is designed for 1 or 2 speakers
per talkback circuit.
Robust versions of talkback intercom points, known as emergency call stations or help
points, are available in many forms and include one or more call buttons. These are
commonly used in parking garages, parking lots and any public space where immediate
assistance might be required.
There are many options for emergency help points such as integrated cameras, strobes
and light beacons for easy identification.
Special Application Speakers/Horns
Valcom offers speaker and horns for specialty areas such as cleanrooms and potentially
explosive environments such a petroleum refineries and grain elevators. If your
application includes areas with unique requirements, give us a call to discuss the best
solution.
High Fidelity Speakers
Valcom interior speakers are commonly used for background music. If your application
requires higher fidelity (retail, lobby areas, etc.) then you may wish to select our Signature
Series speakers which are designed to provide higher fidelity audio.
V-1420
V-1422/V-1422-EC
V-1440
V-1450
High-Fidelity Signature Series Ceiling Speaker
High-Fidelity Signature Series Lay-in Ceiling Speaker
High-Fidelity Signature Series Monitor Speaker
High-Fidelity Signature Series In-Wall Speaker
Design by Location
When designing a public address or intercom system for larger facilities, separate the
facility into logical subdivisions by floor and/or by function. Plan dedicated cabling and
other support products such as power supplies and network switches for each
subdivision.
Doing so will facilitate future maintenance and will logically support zoning.
Determining Zoning
A paging zone is simply a combination of speakers and horns that will receive
announcements simultaneously. Zoning is usually dictated by area functions and
commonality. Usually whole floors of multi-story facilities are considered a zone with sub
zones further dividing the floor. Individual buildings are typically zones as are outside
areas.
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K-12 schools (Kindergarten through 12th grade) are by far the most granulized facilities
with each classroom being a zone (called a station since it will feature talkback capability),
each grade level being a zone, each floor being a zone, etc.
Properly configured individual zones can always be combined into larger groups, like all
call, in system programming.
There is no practical limit to the number of stations or zones in a modern public
address/intercom system.
Plan Cabling to Support Zoning/Granularity
When planning the cabling for speakers/horns in a facility, connecting them all on one
looped cable pull (even if feasible) limits you to one zone of audio. All audio will go to all
speakers due to the common cabling. Conversely, if you connect each speaker on its own
cable all the way back to the main equipment, then the speakers/horns may be easily
configured in any future combination desired. In most installations, a wiring plan between
these 2 extremes is best. Loop speakers in common areas (multiple hallways, restrooms,
etc.) that will always receive common general announcements. Use dedicated cables for
speakers in areas that will likely require area specific audio or omission from general
announcements (classrooms, boardrooms, each floor, lobby, etc.)
System Power
Valcom Self Amplified Speakers and some Valcom Controllers are rated in Valcom Power
Units (VPU). Products that require power have a negative VPU rating and products that
provide power (power supplies and some controllers) have a positive VPU rating. The
resulting sum of the VPUs between power supplies and the products that they are
powering must simply be => zero. It’s simple addition and subtraction, no complex power
formulas are required. Power supplies are independent of speaker zones, so one supply
can power speakers in many zones. VoIP speakers are PoE powered and do not require
separate power supplies. Refer to the published network requirements. In order to
minimize wiring cost and facilitate troubleshooting, it’s best to locate PoE switches and
power supplies in IDF closets within each speaker area.
Feedback Elimination
When a live page is broadcast in the same area from which it is initiated, acoustic
feedback can be an issue. Digital feedback eliminators and Application Servers record
announcements and delay their broadcast until the initiating telephone or microphone is
idle. Therefore, there can be no feedback. Valcom’s Feedback Eliminators and
Application Servers also allow page stacking so that multiple announcements can be
recorded, queued and broadcast sequentially.
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Valcom Self Amplified Speaker Wire Length
Valcom Self Amplified Speakers are connected with UTP cabling. There is a pair of wires
for the audio, and a pair of wires for -24VDC (-48VDC for 30W horns) that is used to
power the integrated amplifier. Speakers that will always receive the same audio can be
looped together with the “tip” side of all speakers connected to one wire in a twisted pair
and the “ring” side of all speakers connected to the other wire in the same twisted pair.
As with anything, there are some guidelines for how many speakers can be looped
together. This is based upon the wire size and the distance of the loop.
Power Pair Wire Run
Number of Speakers/Horns Per Power Run
Power Run Wire Length in Feet (meters)
15/30
1 VPU*
4 VPU*
Flex
5 Watt
24
22
20
18
Watt
Speakers
Speakers
Horns
Horns
AWG
AWG
AWG
AWG
Horns
1000’
1600’
2500’
4000’
4
1
(304 m)
(487 m)
(762 m) (1219 m)
500’
800’
1280’
2025’
7
2
1
1
(152 m)
(243 m)
(390 m) (617 m)
250’
400’
640’
1010’
15
4
2
2
(76 m)
(122 m)
(195 m) (308 m)
125’
200’
320’
500’
30
8
4
4
1
(38 m)
(61 m)
(98 m)
(152 m)
*VPU = Valcom Power Unit
Interestingly, unlike amplifiers, a single power supply may be used to power different
loops of speakers, even if they are connected to different audio outputs.
In both IP and analog systems, in areas where analog speakers or clocks will be used, a
distribution frame should be established to centralize components common to those devices.
This may include power supplies, amplifiers, line level audio distribution points, etc.
Speakers that will always receive the same audio may be looped (connected in parallel).
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Talkback intercom speakers and single speaker zones are typically home run (use a dedicated
cable).
Be certain to observe any published wire length or maximum speakers per output guidelines.
In a purely analog design, Individual area distribution frames will all connect to a main
distribution frame. The Main Distribution Frame is where all audio and clock correction will
originate.
Power supplies, amplifiers and other analog support peripherals for each area are located in,
and distributed from, the local distribution frame.
This practice facilitates troubleshooting and reduces maintenance and cabling cost.
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In systems that utilize IP audio distribution, a Main Distribution Frame is not typically required.
All audio is distributed over the network, converted to an analog format and distributed from the
local distribution frame.
Power supplies, amplifiers and other analog support peripherals for each area are located in,
and also distributed from, the local distribution frame.
This practice facilitates troubleshooting and reduces maintenance and cabling cost.
Note: With full IP solutions (not shown), there are no power supplies or amplifiers. With full IP
systems, every speaker, horn, clock, and gateway simply connects to a properly configured
network. These devices are powered by the network switch (PoE). There are no distance
limitations or system size constraints for full IP solutions.
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Plan System Access
There are no realistic limits for access paths and number of users in a modern Public
Address/Emergency Notification system.
Access is typically accomplished through a telephone system so that any telephone user
on-site (or off-site in some cases) can be granted access. Most often, one or more FXO
(loop start trunk) ports are allocated on the telephone system, connected to the Public
Address/Emergency Notification system, and programmed as a line pool (trunk group).
This line pool allows users to connect to Public Address/Emergency Notification system
via a trunk access code or preprogrammed line key. Session Initiation Protocol (SIP) is
also a popular access method. In either case, the telephone system manages access.
You are never limited to only one access path. In a good design, you will have redundant
paths such as FXO ports on the telephone system + one or more stand-alone access
phones + microphone access, etc.
Determine who will use the system. For each user, what functions will they perform?
a) Make live voice announcements
a. Through a telephone system?
i. Through one or more FXO (loop start trunk) ports?
ii. Through one or more FXS (analog station) ports?
iii. Via Session Initiation Protocol (SIP)?
b. Through a microphone?
1. PC based microphone?
2. Desktop microphone?
b) Launch pre-recorded audio
a. Through pushbuttons?
b. Through a browser?
c. Through a hyperlink?
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Microphone vs. Telephone Access
When adding dedicated page telephones or microphones, there are several things to
consider.
Dedicated page telephones offer the ability to dial select multiple zones or groups in order
to direct your announcement to different areas. They also support two-way hands free
talkback communication. Dedicated page telephones are a great backup to systems that
use a telephone system for primary access. If the telephone system fails, the dedicated
page telephones will still provide full public address/intercom system access.
Microphones are only suitable for one way announcements.
USB microphones, when used with an Application Server, may be used to direct your
announcements to different areas.
Non-USB microphones are suitable for calling one area. They may be added to announce
to an entire facility or to a predefined section of the facility. They do not support talkback
intercom communication. One benefit of non-USB microphones is that they are easily
used by untrained individuals during crisis situations.
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Telephone Speaker Utilization
In most cases, facility telephone set speakers may be included in public address system
broadcasts. This is a very cost effective way of supplementing audio coverage and
enhancing system effectiveness.
Typical System Features
a) Telephone paging
a. Multiple access paths. One per potential simultaneous voice page/intercom
call1. For each path:
i. You can use an FXO port from your phone system
ii. You can use a SIP identity from your VoIP phone system
iii. You can use a dedicated telephone
b) Scheduling
a. Shift change tones
b. Class change tones
c. Automated announcements
d. Music
c) WAV file storage and control
d) Clock synchronization control
e) Emergency messaging
f) Microphone access
g) Remote management
Additional advanced system features include:
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
l)
Automatic door/gate control
Graphical “point and click” message delivery
Facebook™ posts
Twitter™ Posts
Website Posts
LED Sign messaging
Offsite access via telephone line
Speaker supervision
Text to Speech
Automatic Messaging from monitored CAP, RSS, ATOM feeds
IP Camera Integration
PSAP alerting/911 call alert
1
A single system can use any mix of access methods, SIP and FXO, SIP and dedicated
telephone, FXO and dedicated telephone, etc.
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Clock Choices
IP PoE Clocks
Wired Clocks
Wireless Clocks
It may seem odd to discuss clocks in a
document concerning public address system
and intercom design, but it’s really not odd at
all.
Just as a properly designed public address
system is essential for communicating with a
large number of people, a synchronized clock
system is essential for keeping those people
on schedule. Synchronized clocks are
multiple clocks that always display
corresponding time.
This is very important in order to coordinate
the activities of personnel and students.
Without a single time standard, people have
no way to know when it’s time to begin and end the work day, attend meetings or, in the
case of students, assemble for classes.
Many public address systems offer the ability to synchronize clocks so that scheduled
audio may be broadcast when the clocks reach specified times. The use of shift or class
change tones along with synchronized clocks provides an audible notification for listeners
to keep on schedule. It’s very important that the audible notifications and clocks are
coordinated.
There are several clock correction methods that may be used:
Wireless
Wireless clock synchronization, as the name implies, is accomplished through radio
frequency transmission. The master clock or public address system’s integrated master
clock constantly broadcasts the correct time.
A superior system will use frequency hopping technology to avoid interference and will
feature the ability for clocks to rebroadcast any valid time correction signals in order to
propagate the correction signal throughout the facility. Wireless clock systems that do not
include signal repeaters in each clock may require periodic renewal of a site FCC license
and expensive stand-alone signal repeaters.
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Wireless correction is a very good choice for any facility and significantly reduces the cost
of wiring.
Wired Clocks
Wired clocks may use old fashioned synchronous correction protocols or modern 2-wire
digital correction. New installations of wired clocks should always use modern 2-wire
digital correction as synchronous correction takes a significant amount of time to update
the clocks following time changes. 2-wire digital clock correction constantly provides
updated time information and corrects the clocks immediately when time changes or after
temporary facility power failures. 2-wire digital correction is maintenance free and uses a
single pair of Unshielded Twisted Pair wire.
Network Based/IP Clocks
Network based or IP clocks connect to a PoE network port. They are powered from, and
receive correction data from, the network switch. They obtain time from an NTP (Network
Time Protocol) server. These are a good choice for modern facilities that choose to
coordinate time between multiple networked systems with a maintenance free solution.
IP clock correction corrects the clocks quickly after time changes and, should facility
power temporarily fail, immediately upon restoration of the network.
Non-IP Clock Power
Analog display wireless clocks are available with long life battery power or may be
powered with 24vdc over a single pair of Unshielded Twisted Pair wire. Wired digital and
analog display clocks are powered with 24vdc over UTP cable.
Display types
All analog display clocks are available in 16 inch (40.6 cm) and 12 inch (30.48 cm). Digital
display clocks are available with 2.5 inch (6.35 cm) or 4.0 inch (10.16 cm) digits. Digital
display clocks may have 4 digit displays for hours and minutes or 6 digit displays for
hours, minutes and seconds. 12-inch analog display or 2.5 inch digital display clocks work
well in offices, lobbies, break rooms and other small to mid-sized areas. 16-inch display
or 4.0-inch digital display clocks have high visibility and should be used in large rooms
and open common areas.
Analog display clocks are available with custom dials incorporating corporate logos or
other facility related graphics. Custom dials with 24-hour format and/or Arabic numerals
are also available. Clock/speaker combinations units, popular in classroom environments,
are available with digital or analog clocks.
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Mounting
All clocks are available in single sided wall mounted or double sided wall/ceiling mounted
versions.
Time Base
The time displayed on the synchronized clocks will only be as accurate as the time
provided by the master clock or public address integrated system master clock. All
modern systems use either NTP or receive time from GPS satellites; however, if there
are readily available public NTP servers in your region of the world, there is no need to
have both in one system as this simply adds unnecessary cost. Valcom offers a variety
of Master Clocks for use in any application. Contact us for details.
Spacing/wire length guidelines
16 inch (40.6 cm) clocks may be read from as far as 140 feet (43 meters)
12 inch (30.48 cm) clocks may be read from as far as 98 feet (30 meters)
2.5 inch (6.35 cm) clocks may be read from as far as 150 feet (45 meters)
4.0 inch (10.16 cm) clocks may be read from as far as 250 feet (76 meters)
Using 24 AWG UTP for 24V Clocks
1 Clock per
Wire Run
5 Clocks per
Wire Run
10 Clocks
per Wire
Run
15 Clocks
per Wire
Run
20 Clocks
per Wire
Run
Analog
3000’/914 m
1000’/304 m
600’/183 m
400’/121 m
300’/91 m
2.5-inch
Digital
1500’/457 m
500’/152 m
250’/76 m
N/A
N/A
4-inch
Digital
400’/121 m
100’/30 m
N/A
N/A
N/A
Using 20 AWG UTP for 24V Clocks
1 Clock per
Wire Run
5 Clocks
per Wire
Run
10 Clocks
per Wire
Run
15 Clocks
per Wire
Run
20 Clocks
per Wire
Run
Analog
7000’/2130 m
2500’/762 m
1400’/427 m
1000’/304 m
750’/229 m
2.5-inch
Digital
3900’/1189 m
1300’/396 m
700’/213 m
N/A
N/A
4-inch
Digital
900’/274 m
300’/91 m
N/A
N/A
N/A
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Speaker and Clock Accessories and Enhancements
Suggested accessories for a system cannot be determined by speaker types and counts
alone. Details of the installation are also required. Some examples are listed below:
Product
Installation Detail
Round ceiling speakers may require bridges and backboxes, bridges
Round without backboxes or support rings. In some cases, they may also require
Ceiling clock speaker baffles or square surface mount enclosures. We need to
Speaker know the type of surface and environment in/on which the speaker will be
installed to assist in accessory selection.
Lay in Lay in Speakers are designed to replace a ceiling tile. They are available in
Ceiling Imperial measurements 2’ x 2’ or metric measurements 600mm x 600mm
Speaker and do not require any accessories.
Horns may require protective wire cages (guards) if they are in areas
Horns
where damage from vandalism or unintentional ball strikes are possible.
Clocks may require protective wire cages (guards) if they are in areas
where damage from vandalism or unintentional ball strikes are possible.
Clocks
They may also require clock speaker baffles or 2-sided mounting brackets
in certain applications.
If you provide the required installation details, we will happily assist you in selecting
accessories and enhancements.
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Visual Paging
Visual paging is a great option for:
1)
2)
3)
4)
Extremely loud areas
Areas frequented by hearing impaired individuals
Quiet zones
Messages that must repeat for a given period of time
Visual paging or “visual message systems” enjoy maximum effectiveness when LED
signs are used in tandem with speakers or horns. Often flashers or strobes are added to
bring attention to the fact that a message is in progress. LED signs are available both with
and without integrated speakers.
Retrofit Systems
It’s not uncommon for customers, especially K-12 customers, to have interest in reusing
the speakers, cabling, call buttons and clocks from their antiquated intercom/public
address system. If this is the case, we’ll need to know:
1)
2)
3)
4)
The type(s) of speakers that will be reused
How the existing speakers and call buttons are wired
Quantities and tap settings of speakers in all areas
Clock Model Numbers, operating voltage and wiring configuration (# of wires)
Retrofits are easily accomplished using either analog or IP technology. Be aware,
however, that if the existing speakers, cabling, call buttons or clocks are not in good
operational condition, then the resulting retrofit system’s performance will suffer.
See our Best Practices and General Troubleshooting Procedures for information on
assessing existing cabling. An Impedance Meter, also described in this document, may
be used to determine the wattage load of existing common area speakers. This
information is required in order to choose amplifiers.
Since retrofits use both new and existing equipment, it’s important that you and your
customer discuss, and agree upon, your scope of work upfront.
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Reusing Existing Equipment
It’s not unusual for new equipment to be interfaced with previously installed, sometimes
rather dated, equipment. Contractually defining your scope of work for the newly installed
equipment and documenting where your responsibility begins and ends is very important.
There’s always a reason why end users contract new equipment upgrades or
replacement, it’s typically because the old equipment is no longer providing satisfactory
results. However, by reutilizing parts of the old system, they potentially introduce troubles
to the new system.
1) The accuracy of failing electromechanical clocks with worn gears will not increase
because you’ve replaced the master clock.
2) Intermittent push buttons will still be intermittent when connected to new
equipment.
3) Sticking contacts from monitored equipment will still stick when connected to new
equipment.
4) Speakers with broken paper cones will not sound better when connected to new
amplifiers.
5) Intermittent cabling will still be intermittent when connected to new equipment.
The author recalls a site where relays from Valcom equipment were being utilized to
operate 40+ year old electromechanical door locks. These same locks provided a contact
closure when the door was unlocked or ajar. These contacts were connected to Valcom
equipment to provide indication that the door was unsecured.
Several of the doors would not unlock as designed. However, monitoring the relay outputs
of the Valcom equipment verified that the activation contact closures were indeed
operating as designed. Therefore, the locks were at fault. The scope of work was to
provide activation for the lock.
On this same site, several doors would intermittently indicate that they were unsecured
when they were actually closed and locked. By monitoring the inputs of the Valcom
equipment where the “door ajar” contacts were connected, it was obvious that the “door
ajar” contacts were sticking closed from time to time, thus causing the fault.
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Integrating with non-Valcom Equipment
If you plan to interface your new Valcom solution with non-Valcom equipment, you will
need to gather information concerning the desired interface. Depending upon the desired
interface, you will need to know one or both of the following.
1) What does the non-Valcom equipment require from the Valcom equipment?
2) What does the non-Valcom equipment provide to the Valcom equipment?
For audio interface, you will need to know:
1) output levels and impedances
2) input levels, sensitivities and impedances
For contact closure interface, you will need to know the contact voltage/current ratings
and operation.
For data interface, you will need details on the data format and any security credentials.
For voltage triggers, you will need to know the voltage type (ac/dc), level, and current
capacity.
Putting It All Together
With Public Address/Intercom systems, there are typically multiple ways to achieve the
desired end result. For very simple paging systems - typical small to medium sized office/
manufacturing areas, car dealerships or medical/dental offices, Valcom offers the “Easy
as 1-2-3” method of design.
For more complex opportunities, once you’ve selected the features you’ll need, the
number and type of clocks, speakers, horns and zones/stations you’ll need per area, a
quick call to Valcom will result in a suggested equipment list for your job. Note that the
accuracy of the suggested equipment list will only be as accurate and thorough as the
information that you provide.
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Basic Pre-Call Checklist
Are you comfortable with your understanding of how the system will be utilized?
Do you have specific information of the capabilities, Input/Outputs, tap settings of
speakers, capacity of amplifiers, etc. of any existing equipment that will be reutilized?
Have you determined an adequate zoning plan so that announcements can be
broadcast/displayed to target audiences without disrupting everyone?
Have you determined how you’d like to deploy announcements? Speakers/Horns,
Computer pop up alerts, LED signs, etc.
Have you given thought to the type of system you’d like? IP, analog, both
Have you determined the number and type of speakers, horns, clocks and LED signs
required on a per area basis? (Use the worksheet in our Site Survey Form)
Have you selected speaker/horn/clock/LED sign styles?
Do you know ceiling heights and type of ceiling for each area?
Do you know the potential mounting height for ceiling speakers in each area? This may
or may not be the same as the ceiling height.
If areas have drop ceiling, do you know the dimensions of the grid?
For round ceiling speakers, do you have requirements for mounting rings, speaker
bridges and/or backboxes?
For surface mounted speakers, do you have requirements for backboxes?
Have you identified wiring closets in each area to accommodate support products such
as power supplies and network gateways?
Have you gathered details for any non-Valcom equipment?
Have you determined how and from where the system will be accessed?
Do you have information on the available FXO ports and SIP capability of the host
phone system?
Have you determined how many users may be using the system simultaneously?
Have you determined an appropriate feature set for the facility?
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System Design Software
We offer free system design software to aid in designing large complex systems. The
software allows you choose equipment, speakers, enhancements and power supplies. It
supports defining equipment locations (MDF, IDF) that will serve specific facility areas
and, when used properly, results in a printable document featuring the complete
equipment list and a breakdown of equipment by location. Notes may be entered per area
to advise the installer of specific requirements such as the install location of clocks and
speakers.
The tool saves system designs and seamlessly supports inevitable design modifications.
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Common Vertical Market Features
As concern for crisis preparedness grows, K-12 and most other densely occupied facilities
often require both an emergency notification system and a bell/clock/intercom/public
address system. A cost-effective approach is selecting an emergency notification system
that also offers all of the functions of a bell/clock/intercom/public address system.
Benefits of this approach include:
1) Labor savings. Stand-alone emergency notification systems, even supervised
systems, must be tested periodically to verify operation. By utilizing the system
daily for intercom and general announcements, operational testing requires little or
no additional effort.
2) Significant cost saving:
a. Using speakers, visual messaging LED signs and core equipment for both
emergency notification and daily intercom/paging saves on equipment and
infrastructure costs
b. Installation cost to install one comprehensive system will be less than the
installation cost for 2 separate systems
3) One system results in less maintenance.
4) One system results in less training.
5) Daily use means that periodic refresher training is unnecessary.
The RFP is for an
intercom and
clock system.
© 2016-2017 Valcom, Inc. Roanoke, VA
What would it take to
add some emergency
notification features?
The incremental cost
now will be much less
than adding an
emergency
notification system
later.
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K-12 Schools
K-12 educational facilities demand more of their intercom/public address systems than
any other vertical market. They make extensive use of:
Grouping to target messages and bell tones to various grade levels
All call for general announcements
Scheduled tones for class changes
Feedback elimination
A system of synchronized clocks
Two-way hands free talkback communication and call buttons per classroom
Automatic scheduled announcements
Other features of interest to K-12 facilities include:
Countdown (to next class period) clocks and clock correction
Control facility environmental systems
Lockdown and lockdown confirmation
Multi-Language systems
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Announcements over telephone speakers
Panic buttons
Retrofit systems that reuse existing speakers and cabling
Classroom sound reinforcement
Automatic music control for class change periods
District wide announcements
PSAP alerting/911 call alert
K-12 Specific Design Questionnaire
K-12 Specific Design Document
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Higher Education
General and emergency level zoned paging to provide information and locate
personnel
Announcements over telephone speakers
A system of synchronized clocks for a single time standard
Dorm room panic buttons to alert campus police
Campus information system
Emergency IP cameras
Touchscreen incident management
Incident mapping
Incident reporting system
Staff/Student/Parent alerts and notifications
Personal communication device alert
PSAP alerting/911 call alert
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Government/Military
General and emergency level zoned paging to provide information and locate
personnel
A system of synchronized clocks for a single time standard
Airport crash system/radio integration
Base wide communication
Announcements over telephone speakers
Speakers with integrated LED flashers for alerts
Visual message systems
Multi city/state systems
Secure eavesdrop-proof speakers for classified information areas/meeting rooms
Sound masking for privacy
Supervised/automatically monitored systems
Timed (scheduled) music
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Commercial/Industrial
General and emergency level zoned paging to provide information and locate
personnel
A system of synchronized clocks and shift change tones for a single time standard
Background music in lobby / common areas
Automated messaging from facility processes/machines
Automatic system tests
Automated announcements triggered from the fire alarm
Forklift messaging and notification
Loud ringing phone call notification over speakers and horns
Automatic volume adjustment for fluctuating ambient noise levels
OSHA compliance - Alert Tones (often required by OSHA)
Shift change tones/management
Acoustic feedback prevention
Queued announcement stacking
Announcements over telephone speakers
Visual message systems
PSAP alerting/911 call alert
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Healthcare
General and emergency level zoned paging to provide information and locate
personnel
A system of synchronized clocks for a single time standard
Background music in common areas
Two-way hands free talkback intercom in operating rooms
Area of rescue assistance
Button launched pre-recorded coded announcements
6-digit countdown digital clocks used to time medical procedures
Digital signage for Information
Site wide lullaby to welcome new births
Spot sound masking for patient privacy (HIPPA compliance)
Visual message systems
System wide paging
Announcements over telephone speakers
PC pop up alerts (desktop notification)
Acoustic feedback prevention
Queued announcement stacking
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Transportation
General and emergency level zoned paging to provide information and locate
personnel
A system of synchronized clocks for a single time standard
Ruggedized help points/panic buttons at bus stops and train platforms
Access control with two-way hands free talkback intercom
ADA compliance
Automatic emergency information/weather/terrorist act monitor
Two-way hands free talkback intercom to dock drivers/gates
Automated pre-recorded announcements
Visual message systems
Acoustic feedback prevention
Queued announcement stacking
Background music in common areas
Scheduled and manual arrival/departure announcements
Announcements over telephone speakers
Strobe activation
Need more ideas?
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Glossary of Industry Terms
systems, alert tones bring attention
to the impending message.
110 Block
A terminal block used for the
compact
interconnection
of
Unshielded Twisted Pair (UTP)
wiring. 110 blocks are superior for
maintaining the integrity of the twist
in UTP, but require special tools for
troubleshooting.
66 Block
A terminal block used for the
interconnection of UTP wiring. Also
known as a “punch down block” or
“split block”.
A feature of a zone public address
system which allows the user to a
dial a specific code and by doing
so, access all of the speakers
associated with that system. If the
zone public address system
features a talkback capability, the
talkback signal is inhibited during
all call access.
Ambient Noise
Background noise in an area
measured in dBspl.
Air Plenum
Air space above drop ceiling tiles
used for air return. Usually requires
special wiring or conduit to meet
local fire code specifications.
Alert Tone
Alert tone which may precede a
voice announcement from a paging
zone. Alert tones are used in
talkback intercom systems in order
to
discourage
unannounced
monitoring of zones. In one way
© 2016-2017 Valcom, Inc. Roanoke, VA
All Call
Amphenol
A 50 connection point conductor
connector commonly used for
telephone
equipment
and
overhead public address systems.
Amplifier
An electronic device used to
increase a signal’s power or
amplitude.
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Atom Feed
Backbox
Atom Syndication Format (ATOM
Feed) is an XML language used for
web feeds.
Speaker housing or enclosure
designed to provide coverage for
the rear of a ceiling speaker. This
coverage may be required by local
building codes for air plenum type
ceilings or may be used in other
type ceilings to protect the speaker
from dust and debris accumulation.
Commonly used in conjunction with
a bridge.
Attenuation
Reduction in magnitude of any
electrical parameter of a signal, on
passing along any transmission
path. In public address systems,
this is typically used to describe the
reduction of audio level.
Audible Frequency
Frequencies detected by the
human ear, usually between 20
and 20,000Hz.
Automatic Gain
A device for holding the output
volume of an audio source
consistent despite variations in the
input signal.
Automatic Volume Control
(Antiblast Control)
An automatic potentiometer. This
device monitors the ambient noise
level and adjusts the audio output
of public address speakers or
horns
accordingly.
(a.k.a.
Automatic Volume Control).
© 2016-2017 Valcom, Inc. Roanoke, VA
Bandwidth
The range of signal frequencies
(Hertz) that a circuit or network will
effectively reproduce or pass.
Battery Backup
An alternate power source that is
used in the event of a loss of a
system’s primary power.
Battery Feed (BF)
DC voltage present on POTS
telephone lines used for signaling
and for powering plain old
telephones.
BGM
An abbreviation for Background
Music. BGM is subliminally
broadcast music within a facility.
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Bridge
An optional hardware device
utilized for ceiling speaker support.
It is generally placed in a drop type
ceiling so that the frame of the
bridge rest on the support grid
system thereby alleviating any
stress to the ceiling tile.
Bridging Clips
Metallic clips used for connecting
the two halves of a split punch
down block.
Browser Based Server
A network server that is accessed
via a web browser thus making it
accessible from any device
capable of accessing websites.
Butt Set (Lineman’s Handset)
A self-contained test telephone
primarily used for telephone
installation troubleshooting. Used
to listen to audio signals and
provide telephone access to public
address systems.
communication from the talkback
speaker location. The conversation
is initiated when the recipient
device answers the call.
Calling Party Control (CPC)
A signal sent from a phone system,
or a telephone service provider, to
the
telephone
subscriber's
equipment to indicate that the
calling party has hung up. This is
typically accomplished via an Open
Loop Disconnect where the battery
feed voltage is momentarily
removed from the trunk.
Central Office (C.O.)
The switching equipment that
provides local exchange telephone
service for a given geographical
area. The main distribution center
for telephone service to a particular
area. In addition to basic telephone
switching, C.O.s may also provide
Centrex or Essx service and direct
inward dial (DID) service.
C.O. Line Port (Loop Start)
Call Button
A momentary switch used with
talkback speakers to notify a
recipient device (telephone) that a
user is requesting two-way
© 2016-2017 Valcom, Inc. Roanoke, VA
A key system or PBX (PABX) C.O.
line circuit which can be used to
access most Valcom Page Control
Interface Units. C.O. line ports
connect to dial tone sources.
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Centrally Amplified System
An old-fashioned type of public
address system which utilizes
central amplifiers.
Centrex (Hosted Telephone
Service)
Service provided through the C.O.,
which provides the end user with
many or all of the features of a PBX
without the expense or upkeep of a
private switch. The service is
purchased from the C.O. and
requires
no
“on
premises”
equipment.
Closed Loop
DC load applied across tip & ring
which completes the circuit and
allows loop current to flow. This
state indicates a request for service
from the control unit, station port or
central office.
critical
warnings
over
data
networks. CAP allows a consistent
warning
message
to
be
disseminated simultaneously over
many different warning systems,
thus
increasing
warning
effectiveness while simplifying the
warning task.
Common Battery
A system of supplying direct
current for the telephone set from
the C.O. (a.k.a. Talk Battery)
Contact Closure
A relay (electromechanical switch)
or pushbutton, which provides a
short circuit upon activation.
Closures are used to activate
various features on page controls
as well as to activate certain
controllers during page port
access.
Combination Paging
Control Unit
A public address system in which a
talkback capable page control unit
is used in conjunction with both
talkback and One-Way speakers.
(a.k.a. mixed paging)
With respect to analog public
address systems, a control unit
provides the interface to the
telephone system and may also
provide various features.
Common Alert Protocol
CPC
The Common Alerting Protocol
(CAP) is a simple, general format
for sending emergency alerts and
© 2016-2017 Valcom, Inc. Roanoke, VA
See Calling Party Control
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Cross-Connect
dBspl
A connecting device facilitating the
termination of cables and their
interconnection,
and/or
cross
connection, typically by means of a
patch cord or jumper.
Sound pressures described
terms of dB (decibels)
Cross Connection
(Interconnect)
Dial Tone
The tone that is heard by the caller
when a multi-zone page control is
first accessed.
Dispersion Angle
Methods of using cross-connect (either
with or without a patch cord or jumper).
Crosstalk
An undesired voice-band audio
transfer from one circuit or
conductor to another (usually
adjacent).
Daisy Chaining Cable
Wiring multiple devices on one
continuous looped wire run.
Compare: Home Run
dB (Decibel)
The decibel (dB) is a logarithmic
unit used to express the ratio of two
values of a physical quantity,
often power or intensity. One of
these values is often a standard
reference value, in which case the
decibel is used to express
the level of the other value relative
to this reference.
© 2016-2017 Valcom, Inc. Roanoke, VA
in
With regard to speakers and horns,
this is the entire angle off axis at
which
the
sound
pressure
diminished by 6 dBspl.
Dynamic Host
Protocol (DHCP)
Configuration
DHCP allows network endpoints to
dynamically request an IP address
when they are starting up. With
DHCP, if an endpoint is moved
from place to place, it will be
assigned a new address in each
location. When relying upon
DHCP, it’s important to provide
battery backup for the DHCP
server and any switches and
routers so that network endpoints
do not self-assign a static address
following power failures.
Distributed Self-Amplified
System
The modern way to integrate
analog
public
address
announcements with a telephone
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system in which each speaker has
a built-in amplifier and volume
control,
(a.k.a.
the
Valcom
System).
Compare:
Centrally
Amplified System
Dry Contact Closure
A switchable set of contacts with no
potential difference between them
or to any other reference point.
Dual-Tone Multi-Frequency
(DTMF)
Use of two simultaneous voice
band tones for signaling or dialing
on a telephone keypad.
Equalizer (EQ)
A device that modifies an audio
signal through the use of multiple
adjustable filters.
Explosion-Proof
Eavesdropping
The act of monitoring an area
without knowledge or consent of
the occupants.
Ethernet Distribution Point
(EDP)
Explosion-proof
equipment
is
designed such that, should ignition
of an explosive gas occur within the
device, the device will contain the
explosion.
Extension Port
A physical location where Ethernet
distributed audio is returned to an
analog signal.
Electric Strike plate
An electro-mechanical door lock.
Endpoint
In Valcom VoIP systems, the terms
endpoint and gateway are used to
describe the actual Valcom
© 2016-2017 Valcom, Inc. Roanoke, VA
network connected equipment. In
general, the term endpoint is used
to describe devices that provide
information to users without any
interaction on the user’s part
(speakers, horns, LED signs)
where gateway is the term used to
interface to support equipment
(audio sources, telephones, relays,
etc.)
A port on a telephone system that
is intended for connection to a
system telephone or station level
paging adapters. See Station Port.
Federal Communications
Commission (FCC)
A U.S. government agency that
regulates/monitors the domestic
use of electromagnetic spectrum
for communications.
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Feedback
amplifies a specified audible range
with equal amplitude or intensity.
The process of returning a fraction
of the output energy of an energy
converting device to the input. The
circuit that transmits the feedback
signal to the input is the beta circuit;
the circuit containing the active
device, which generates the output
signal, is the mu circuit. In audio
amplification systems, feedback
results in an undesirable system
wide squeal.
Feedback Elimination
FXO Port
Foreign Exchange Office - See
C.O. Line Port
FXS Port
Foreign Exchange Subscriber - see
also Extension Port, Station Port
Gateway
The rate in hertz (cycles per
second) at which a signal pattern is
repeated.
In Valcom VoIP systems, the terms
endpoint and gateway are used to
describe the actual Valcom
network connected equipment. In
general, the term endpoint is used
to describe devices that provide
information to users without any
interaction on the user’s part
(speakers, horns, LED signs)
where gateway is the term used to
interface to support equipment
(audio sources, telephones, relays,
etc.)
Frequency Response
Graphical User Interface (GUI)
A measure of the effectiveness
with which a circuit, device or
system transmits the different
frequencies applied to it. The way
in which an electronic device (mic,
amp or speaker) responds to
signals having a varying frequency.
This is a measurement of how well
an amplifier reproduces and
A visually displayed method of
allowing users to control a system
or systems.
A method of digitally delaying live
PA system announcements until
the originating device is returned to
an idle state. This breaks the
feedback loop by delaying the
announcement.
Frequency
© 2016-2017 Valcom, Inc. Roanoke, VA
Granularity
The extent to which a system can
be subdivided. In analog systems
this is dictated by the number of
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audio outputs of the control
equipment and the system cabling.
Head End Equipment
The portion of a public address or
telephone installation at which all of
the system components originate.
Ground
An electrical connection to the
earth or to a common conductor
which is at a reference potential
that serves as a reference point for
all other potentials in the circuit.
Hertz (Hz)
A unit of measurement used to
indicate the frequency of sound or
an electrical waveform.
Ground Start
Home Run
With ground start signaling, a
telephone
immediately
upon
entering
an
off-hook
state,
requests service from the C.O. by
applying a ground to the ring lead
of the tip and ring pair. The C.O.
responds and indicates reparation
to receive digits, by placing a
ground on the tip lead of the tip and
ring pair.
Group
A combination of zones or LED
signs within a multi-zone public
address system used to direct
announcements to a target
audience without disrupting other
areas.
Half-Duplex
A circuit that carries information in
both directions, but only in one
direction at a time.
© 2016-2017 Valcom, Inc. Roanoke, VA
Providing a dedicated wire pair to
each speaker in a PA system.
Compare: Daisy Chaining Cable.
Hosted PBX
A VoIP based telephone system
with no “on premise” telephone
switch. Hosted PBXs are operated
and maintained by a Voice-over-IP
(VoIP) service provider.
Impedance
A measure of the response of an
electric circuit to an alternating
current. The current is opposed by
the capacitance and inductance of
the circuit in addition to the
resistance.
Inhibit
A feature on certain page controls
which cancels or inhibits the public
address speaker audio whenever
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two phones are off-hook on the
page control’s tip and ring. This
feature is activated when each of
the telephones provided an “A
lead” ground to 10k resistors which
are common to the inhibit terminal.
environment. In general terms,
intrinsically
safe
equipment
consumes <= 300 mA from a <=
29-volt source. A simpler view is to
say that power must be less than
1.3 W.
I/O
Insertion Loss
Insertion loss is the ratio of output
power to input power, expressed in
dB, resulting from the insertion of a
device
in
a transmission
line or optical fiber. A device that
that produces 0.8 watt of power
when 1 watt of power is applied to
the input would have 0.968 dB
insertion loss.
Intermediate Distribution Frame
(IDF)
An extension of the main
distribution frame (MDF). The IDF,
usually at some distance from the
MDF, is the location where sub
elements of the telephone or public
address system are distributed to a
particular area of an installation.
Intrinsically Safe
Line Level Audio
A pre-amplified, industry specific,
audio
signal
level.
Usually
described in terms of dB or volts.
Loop Start
The usual method of signaling an
off-hook or line seizure, where one
end closes the loop and the
resulting current flow is detected by
a switch at the other end. With loop
start, the telephone upon entering
an off-hook state, draws loop
current from the C.O. thereby
signaling that service is being
requested.
Loss
Intrinsically safe equipment does
not have the potentional to cause
ignition
in
an
explosive
© 2016-2017 Valcom, Inc. Roanoke, VA
A system input or output.
Connection points where a system
integrates with other equipment.
Undesired (typically) attenuation of
a signal from any cause.
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Main Distribution Frame (MDF)
The location in a telephone or
public address installation where
all of the elements which comprise
that system originate and/or
interface with the public telephone
network.
or a peripheral common audible
ringing device. Night ringing
provides a signal, usually over the
public address system, to indicate
that a telephone line is in a ringing
state.
Noise
Any undesired audio signal.
Meet Me Page
Non-Polarized
A feature where following a general
page, the paged party may dial a
code at an extension telephone
and by doing so, secure a private
talkpath to the paging party and
subsequently, free the page path
for additional use.
Multicast
In networking, a method of
addressing Ethernet packets so
that they are received by multiple
network endpoints. Primarily used
as a method of bandwidth
conservation.
Multimodal Emergency Mass
Notification
An emergency alerting system
capable
of
disseminating
information in many modes like
voice, text, social media, email, etc.
Night Ring (loud Ringing)
Not sensitive to the applied signal’s
polarity.
NTP Server (Network
Protocol Server)
Time
A server, local or remote, that is
defined to provide time to other
network endpoints and servers,
NTP servers provide a single
enterprise-wide time standard for
networked equipment.
Off-Hook
The condition that indicates the
active state of a customer
telephone circuit. This refers to the
early days of telephony in which the
telephone receive was removed
from an actual hook/switch in order
to place a call.
A feature which provide either by a
telephone system, a page control
© 2016-2017 Valcom, Inc. Roanoke, VA
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Off Premise Extension (OPX)
Page Control Lead (PC)
A phone extension located in a
different building from common
equipment.
An output terminal on select page
control units that is connected
internally through a N.O. relay to
system ground. Whenever the
page control is accessed, the page
control terminal is switched to
ground potential. This terminal is
useful for providing ground to
external relays.
One-Way Paging
Public address announcement
without the benefit of hearing
response from the paged area.
Paging System
On-Hook
See Public Address System
The state in which a telephone
inactive. This refers to the early
days of telephony in which the
telephone receive was returned to
an actual hook/switch at the
conclusion of the call.
PABX or PBX
Open Loop Disconnect
See Calling Party Control
Override Tip & Ring
This feature is usually accessed
through a separate tip and ring
input and allows any audio input
from this tip and ring to override all
other pages in progress. Override
tip and ring does not necessarily
provide automatic access to an all
call.
Line Pool
See Trunk Group
© 2016-2017 Valcom, Inc. Roanoke, VA
A private (automatic) branch
exchange is a telephone system
that provides telephone switching
services within business or private
establishment. PBX’s provide 2 or
3-digit access from station to
station as well as many other
features. The telephone terminals
used with a PBX are generally of
the industry standard type.
Page Port
An audio output provided by a
telephone system. Usually the
page port is accessed by dialing a
code or selecting a dedicated line
key.
Parallel Connection
Connection of system elements
(typically speakers or horns) such
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that like connection points are
common.
Phantom Zone
This term is used to describe a
“non-background music” zone
output on a single zone page
control. Single zone page controls,
which provide a phantom zone, will
always have dual speaker outputs,
one with BGM and one without
BGM.
Pinout
The physical pattern of connection
points for a device.
Plain Old Telephone Service
(POTS)
Single line residential rotary dial
service. Quite often a 500 (rotary
desk) or 2500 (touch tone desk)
telephone may be referred to as a
“POTS telephone”.
Port Mirroring
Also
known
as
SPAN
(Switched Port Analyzer), is a
method of monitoring network
traffic. With port mirroring enabled,
the switch sends a copy of all
network
packets
seen
on
one port (or an entire VLAN) to
another port, where the packet can
be analyzed.
© 2016-2017 Valcom, Inc. Roanoke, VA
Power Over Ethernet (PoE)
A method of powering network
endpoints through the same cable
used to provide network traffic.
PoE eliminates the need for
separate power cabling and
simplifies system installations.
Potentiometer
This is a variable resistor. A
movable sliding contact is used to
vary
the
potentiometer’s
resistance.
Public Address System
A voice amplification system used
to provide audible information
throughout a facility or enterprise.
Relay
An
electromechanical
device
comprised of a coil and various
sets of contacts (determined by the
relay selected). When a voltage is
applied to the coil, a magnetic field
is induced around the coil. The
magnetic field attracts metallic,
movable contacts and creates
either a closed contact or an open
contact or various combinations.
Relay coils are rated in acceptable
levels of activation voltage and
current. Relay contacts are rated in
the maximum voltage and current
that they can switch. Often, low
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rated relays are used to actuate
higher powered relays (a.k.a. slave
relays) in order to control power
intensive loads. Relay contacts that
are open in an idle state (relay coil
not energized) are referred to as
Normally Open (N.O.). Relay
contacts that are connected
(shorted) in an idle state (relay coil
not energized) are referred to as
Normally Closed (N.C.).
Repeat Alert Tone
The alerting signal to the
subscriber or terminal equipment.
Also the name of the one conductor
of a telephone wire pair,
designated by R. Also, One side of
a line level audio pair.
Ring Cadence
The pattern of ringing a telephone
terminal.
Ring Voltage
A tone heard through a talkback
speaker every 15 seconds to
prevent eavesdropping.
Remote Intermediate
Distribution Frame (RIDF)
Voltage that is applied to a POTS
telephone or telephone system in
order to signal an incoming
telephone call.
Ring back Tone (RBT)
A physical location where the
Ethernet extension of a Valcom
Class Connection ES system’s
ribbon cable terminates. A remote
VERCA or VECPU6-EXP card
location.
Return Loss
Return loss is the amount of power,
expressed in dB that is reflected
back to a transmission source often
caused
by
an
impedance
mismatch.
© 2016-2017 Valcom, Inc. Roanoke, VA
Ring
In telephony, it is a progress tone
heard by the calling party, which
indicates that signaling (ringing) is
being provided to the called party.
Ringer
A device that produces audible
signaling in response to ring
voltage or contact closure.
RSS Feed
Really Simple Syndication Format
(RSS Feed) is an XML language
used for web feeds.
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Scalability
The ability for a system to increase
or decrease in proportion to a
facility’s needs.
Sensitivity
The level of audio signal into an
amplifier required to achieve rated
amplifier output.
Series Connection
Multiple circuit elements that are
connected so that the same current
flows through each of them.
Sound Reinforcement
Amplification of a line of site
speaker’s voice such as used in
auditoriums,
classrooms
and
lectures halls.
Stand Alone System
A system that does not require the
support of subsequent system(s).
Side Tone
The portion of the talker’s voice
which is fed back to his receiver
intended to discourage the talker
from speaking too loudly or too
softly.
SIP (Session Initiation Protocol)
Session Initiation Protocol (SIP) is
a communications protocol for
signaling
and
controlling
communication sessions. SIP
telephones, Valcom IP speakers
and many Valcom IP gateways
may be used with IP telephone
systems that support SIP.
© 2016-2017 Valcom, Inc. Roanoke, VA
Endpoints defined as SIP Stations
must periodically register with the
phone system. Gateways defined
as SIP Trunks do not require
registration however; do require
route programming in the phone
system.
Splash Tone
A tone that immediately precedes a
voice announcement on hands free
talkback
systems
(prevents
eavesdropping).
Station (Intercom)
A talkback speaker and call button
combination allowing users to
request assistance from the
speaker location.
Station Level Access
Station Level Access is a way of
accessing
public
address
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equipment via an incoming phone
line or station port, rather than
through a KSU or PBX page port or
trunk port. Users must dial an
extension number or telephone
number in order to execute a page.
Station level access requires
appropriate disconnect signaling to
indicate that the origination
telephone has returned to an idle
(on-hook) state.
Switch
Station Port
See Electric Strike plate.
A type of public address system in
which individuals in the paged area
can respond through the public
address speakers of horns.
Talkback speakers are speakers
designed to be used with talkback
controllers and are typically 25-volt
or 45 ohms.
Subscriber
Telephone Terminal
A telephone service customer.
Another term for telephone.
Telephone terminals may be
proprietary to a particular system or
may be designed to work with
many telephone systems.
An output on a telephone system
where a POTS telephone terminal
is connected.
Strike plate
Supervision (speaker or system
supervision)
This is an automatic method of
monitoring a public address or
emergency
mass
notification
system and reporting potential
faults. Notification may be via email, audible or visual alert or both.
© 2016-2017 Valcom, Inc. Roanoke, VA
A generic term for a KSU or PBX.
In networking, a device which
connects endpoints to the network.
Talk Battery
DC voltage applied through a trunk
used to power a POTS telephone.
Talkback
Telephony
Products and services related to
the telephone industry.
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Time Clock Tone
Trunk Port
A single tone broadcast through
the public address system when a
time clock controlled dry contact
closure is applied to an appropriate
signaling device.
See C.O. Line Port.
Tip
Unicast
In networking, this is a method of
addressing Ethernet packets so
that they are received by one
network endpoint.
One conductor of a telephone wire
pair, designated by T; usually the
more positive of the two. One side
of a line level audio pair.
UPS
Tip & Ring
UTP
The terms used to identify single
pair telephone station wiring. The
tip conductor usually has a positive
potential with respect to the ring
conductor. In analog public
address systems, a line level audio
pair.
Unshielded twisted pair cabling.
Often referred to as CAT 3/5/6.
UTP offers many advantages over
other types of infrastructure.
Trunk
A transmission channel that
connects two switching machines.
In telephony a trunk is a POTS
telephone line.
Trunk Group
Two or more trunk ports that
serving the same special purpose
for inbound or outbound calls.
© 2016-2017 Valcom, Inc. Roanoke, VA
Uninterruptible Power Supply. A
system of providing system power
should facility ac power fail.
Valcom Power Unit (VPU)
One Valcom power unit is equal to
and defined as, 50mA @ negative
24 volts dc. Valcom power units
were devised in order to aid in the
determination of total system
power required when configuring a
Valcom public address system.
The use of negative voltage is a
nod to the world of telephony which
also uses negative voltage.
Negative and positive voltages are
equally effective and simply use
different reference points. Valcom
products are rarely polarity
sensitive.
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Voice-grade Line
A local loop or trunk, having a
bandpass of approximately 300 –
3,000Hz.
standard for storing an audio bit
stream on PCs. WAV files are
recorded in various bitrates and
formats.
XLR Connector
Voice Operated Switching (VOX)
Provides the ability to activate a
device simply by the presence of a
specific level of audio signal.
VoIP (Voice Over IP)
A modern-day approach to
distributing audio via a data
network. VoIP systems have many
advantages over analog systems
and provide long term cost saving
and inherent supervision.
A connector usually utilized for the
connection of a microphone to its
associated cable. The pin count of
an XLR connector may vary from
three to seven pins.
Zone
One or more speakers or horns,
typically sharing common wiring,
that always receive the same
audio.
Voltage
A measure of the electrical force
that causes current flow in a circuit.
VSP
Valcom System Practice. Term
used for some Valcom installation
manuals.
WAV File
Waveform Audio File (WAV) is a
Microsoft & IBM audio file format
© 2016-2017 Valcom, Inc. Roanoke, VA
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Let’s Not Make Assumptions
We want to provide you with an accurate equipment list and design.
With minimal information, we have to make assumptions. Assumptions can cost you
money. For example, it you only tell us that you need a 4 zone IP based system with 3
horns and 6 wall speakers, look at 3 possible designs that result.
© 2016-2017 Valcom, Inc. Roanoke, VA
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4 Zones with 3 horns and 6 wall speakers
© 2016-2017 Valcom, Inc. Roanoke, VA
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MDF
Speakers
MDF
Area A
Speakers
MDF
Area A
IDF 1
Speakers
IDF 1
Speakers
IDF 2
Speakers
IDF 2
Speakers
IDF 3
Speakers
IDF 3
Speakers
Area B
Area A
IDF 1
Speakers
IDF 2
Speakers
IDF 3
Speakers
Area B
IDF 4
Speakers
IDF 4
Speakers
IDF 5
Speakers
IDF 5
Speakers
IDF 6
Speakers
IDF 6
Speakers
Area C
Area C
Figure 1
Figure 2
Speakers
Area B
IDF 4
Speakers
IDF 5
Speakers
IDF 6
Speakers
Area C
Figure 3
When designing a public address/intercom system with limited information such as speaker & clock counts, speaker & clock
types and the total number of zones for each area, you have to make assumptions. Assuming that all of the control equipment
will be physically located in one location (MDF) will typically result in a less than ideal design.
The diagrams above represent designs with one zone, two zones and six zones respectively with all of the control equipment
located in the MDF. Determining the equipment lists for these would be very simple, however, since all speakers and clocks
are being powered from the MDF, your installation costs would increase due to the need for more, and often heavier gauge,
cabling.
MDF
Speakers
Speakers
MDF
Speakers
IDF 1
IDF 2
Speakers
IDF 2
Speakers
IDF 3
Speakers
IDF 3
Speakers
Speakers
IDF 1
IDF 2
Speakers
IDF 3
Speakers
Power Supplies
Power Supplies
Power Supplies
Power Supplies
Power Supplies
Power Supplies
IDF 4
Speakers
IDF 5
Speakers
IDF 6
Speakers
Power Supplies
Power Supplies
IDF 4
Speakers
Power Supplies
Power Supplies
Area B
IDF 5
Speakers
Speakers
IDF 6
Speakers
IDF 5
Speakers
IDF 6
Speakers
Power Supplies
Power Supplies
Power Supplies
Power Supplies
Figure 4
IDF 4
Power Supplies
Power Supplies
Area C
Speakers
Power Supplies
Area B
Area B
Power Supplies
Speakers
Area A
Area A
Area A
IDF 1
MDF
Power Supplies
Power Supplies
Power Supplies
Area C
Figure 5
Area C
Figure 6
A better design would involve knowledge of each IDF’s required speaker & clock quantity, speaker & clock type and zone count.
This way, it’s possible to design so that control & support equipment may be selected on a “per IDF” basis.
This reduces cost by minimizing required cable gauge and the number of MDF distribution cables.
© 2016-2017 Valcom, Inc. Roanoke, VA
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LAN
VoIP
Adapter
MDF
Speakers
Power Supplies
LAN
VoIP
Adapter
MDF
Area A
Area A
VoIP
Adapter
IDF 1
VoIP
Adapter
IDF 2
Speakers
Power Supplies
Multi-zone
VoIP
Adapter
Speakers
Power Supplies
Power Supplies
IDF 1
Zone 1 Speakers
Zone 2 Speakers
LAN
VoIP
Adapter
Speakers
Power Supplies
IDF 3
LAN
Zone 1 Speakers
Multi-zone
VoIP
Adapter
Speakers
Power Supplies
IDF 2
Area B
Area B
VoIP
Adapter
IDF 4
Zone 2 Speakers
Power Supplies
Multi-zone
VoIP
Adapter
Speakers
Power Supplies
Power Supplies
IDF 1
Zone 1 Speakers
Zone 2 Speakers
LAN
VoIP
Adapter
VoIP
Adapter
IDF 5
Speakers
Power Supplies
IDF 6
Speakers
Power Supplies
LAN
Zone 1 Speakers
Multi-zone
VoIP
Adapter
IDF 2
Zone 2 Speakers
Power Supplies
Area C
Area C
Figure 7
Figure 8
Sometimes analog designs involve using Ethernet to distribute audio. This may be accomplished by using VERCA cards, VECPU6EXP cards, VoIP audio gateways, and/or IP speakers. If the design has only one zone per IDF, as shown in Figure 7, then we’ll
need to know how many IDFs will be involved, and the quantity and types of speakers & clocks that will be connected to each.
If the design involves multiple zones per IDF, as shown in Figure 8, then you will need to know how many IDFs will be involved, the
quantity and types of speakers that will be connected to each and how many zones each IDF will serve.
© 2016-2017
Valcom,
Inc.IDFs
Roanoke,
www.Valcom.com
for Updates
- https://goo.gl/wfNYHC
It’s common to have
both single
zone
andVA
multi-zone
IDFs inCheck
the same
design.
Page 60
LAN
VoIP
Adapter
IDF
Speakers
Power Supplies
Area A
LAN
VoIP
Adapter
IDF 1
VoIP
Adapter
IDF 2
Speakers
VoIP
Adapter
IDF 3
Speakers
Speakers
Power Supplies
Power Supplies
Power Supplies
Area B
LAN
VoIP
Adapter
Power Supplies
VoIP
Adapter
Power Supplies
VoIP
Adapter
Power Supplies
IDF 4
Speakers
IDF 5
Speakers
IDF 6
Speakers
Area C
Figure 9
If a design is fully IP based, meaning every speaker and horn is an endpoint on the network, then you just need total speaker
counts per type. Full IP systems are, by far, the easiest type to design and implement.
If a design is IP based, but involves audio gateways to analog speakers, then the same questions will apply:
If the design has only one zone per IDF, as shown in Figure 9, then you need to know how many IDFs will be involved, and the
© 2016-2017 Valcom, Inc. Roanoke, VA www.Valcom.com Check for Updates - https://goo.gl/wfNYHC Page 61
quantity and types of speakers that will be connected to each.
VoIP
Adapter
LAN
Speakers
IDF
Power Supplies
Area A
Multi-zone
VoIP
Adapter
Power Supplies
IDF 1
Zone 1 Speakers
Zone 2 Speakers
LAN
Zone 1 Speakers
Multi-zone
VoIP
Adapter
Zone 2 Speakers
IDF 2
Power Supplies
Area B
Multi-zone
VoIP
Adapter
Power Supplies
IDF 1
Zone 1 Speakers
Zone 2 Speakers
LAN
Zone 1 Speakers
Multi-zone
VoIP
Adapter
IDF 2
Zone 2 Speakers
Power Supplies
Area C
Figure 10
If the design involves multiple zones per IDF, as shown in Figure 10, then you simply need to know how many IDFs will be involved,
and the quantity and types of speakers that will be connected to each and how many zones each IDF will serve.
© 2016-2017 Valcom, Inc. Roanoke, VA
www.Valcom.com Check for Updates - https://goo.gl/wfNYHC Page 62
Disclaimer
Note that any applicable standards by official regulatory agencies or ANSI/TIA/EIA/IEEE
should always be observed. In the case of conflicting information, these standards shall
prevail.
The suggestions provided may or may not be suitable for your intended application.
Please consider this information carefully before incorporating it into your system design.
Valcom disclaims any responsibility for accuracy or completeness.
Valcom is not responsible for the content found via hyperlinks within this document.
Content was evaluated and found appropriate and relevant at the time of publication.
This document supersedes all previous versions. Please check for updates at the
following URL - https://goo.gl/wfNYHC
We’d like to hear from you!
Valcom, Incorporated
5614 Hollins Rd
Roanoke, VA 24019 U.S.A.
1-540-563-2000
Regular Business Hours are Monday – Friday
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Engineered, Built and Supported In The U.S.A!
© 2016-2017 Valcom, Inc. Roanoke, VA
www.Valcom.com Check for Updates - https://goo.gl/wfNYHC Page 63
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Public Address System Design

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