CTLOOP
System Description
P/N 762-90100H
April 1998
 1998 Teledata Communications Ltd. All rights reserved.
Teledata Communications Ltd. reserves the right to alter the equipment specifications and descriptions in this publication
without prior notice. No part of this publication shall be deemed to be part of any contract or warranty unless specifically
incorporated by reference into such contract or warranty.
The information contained herein is merely descriptive in nature, and does not constitute a binding offer for the sale of the
product described herein.
File: 90100h.doc saved 28/04/98 11:03
CTLOOP System Description
TABLE OF CONTENTS
CHAPTER 1
1
Introduction
1
CHAPTER 2
5
System Configuration
5
CHAPTER 3
7
Features
7
Interfaces
7
Exchange Side
Subscriber Side
7
7
Advanced Management
8
Power System
8
CU
HU
8
8
8
8
9
9
9
Local Power Feeding
Remote Power Feeding
Batteries
Two-Pair Remote Power Feeding
Power Monitoring
Backup Pair (Option)
9
Auto-Recovery
10
Auto-Configuration
10
CLASS (CLI Support)
10
CHAPTER 4
11
Functional Description
11
CU and HU Line Interface Modules
11
CU Trunk Interface Modules
12
HU Trunk Interface Modules
12
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Introduction
CHAPTER 5
13
Modules
13
CU
13
HU
14
CHAPTER 6
15
Management and Maintenance
15
Management Unit (MU)
15
General Tests
18
Remote Subscriber Loop Tests
18
Voice Frequency Test [F]
Loop Tests
19
19
Alarms and Indicators
19
Alarm Types
20
CHAPTER 7
21
Technical Data
21
Power Source Requirements
CU
HU
RPF
Mechanical Data
CU
HU
RPF
21
21
21
21
21
21
21
21
Environmental Conditions
22
Reliability (MTBF)
22
CU
HU
Optional Items
22
22
22
CHAPTER 8
23
Abbreviation and Acronyms
23
Page iv
P/N 762-90100H
CHAPTER
1
Introduction
CTLOOP is a state-of-the-art pair-gain system serving small groups of telephone
subscribers. It provides telephone companies with an effective tool that can
immediately satisfy customer demand for new telephone services.
CTLOOP, as part of the customer access network, provides the most advanced and
cost-effective solution in cases where the local access network requires:
• expansion and enhancement to areas where the existing infrastructure is limited
• immediate provision of services to subscribers
• upgrading of services
• provision of services to small groups of subscribers
• simple installation in urban areas where telephone cabling is very complex and
expensive
CTLOOP provides immediate service without the cost and delay involved in
planning of the network and in the installation or replacement of copper wires. It
is mostly effective in cases where areas convert from residential to commercial
use, in historical landmarks where tearing up streets is not practical and very
expensive, and in areas of rapid development.
CTLOOP uses advanced digital transmission technology for upgrading an existing
copper wire pair to accommodate up to 10 voice channels, with the added
advantage of spare transmission capacity for use in future applications.
CTLOOP is transparent to both the local exchange and the subscribers: service is
provided as if the subscribers were connected directly to the exchange.
A major advantage of the system is that it can be incorporated into the existing
communication system without the need for significant investment in additional
infrastructure.
CTLOOP can be installed in point-to-multi-point configuration.
CTLOOP supports connections to POTS, pay phones, faxes, data modems. It
supports full 12/16 kHz metering pulse for pay phones, with optional polarity
reversal.
CTLOOP is composed of two units:
• Central Unit (CU) - located on the exchange side
• Home Unit (HU) - located on the subscriber side
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Introduction
:
:
Central Unit (CU)
Home Unit (HU)
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CTLOOP System Description
The CU is connected to the local exchange (either analog or digital) on one side,
and on the other side it is linked to the HUs via trunk lines (2W, 784 kbps).
Each CU can serve up to 12 HUs. Each HU is contained in a compact cabinet, and
can serve up to 10 subscribers. The HU may be mounted on a wall (indoors or
out), on a pole, or in a street cabinet.
The CU and HU communicate with each other through the 2W, 784 kbps HDSL
digital link, in accordance with ETSI RTR/TM-03036.
CTLOOP automatically checks which cards are installed in the CU, and
configures the system accordingly, making installation and commissioning easy.
CTLOOP also offers extensive monitoring and testing capabilities with
administration tools, reducing maintenance costs while pinpointing network
problems. Each subscriber line connected to CTLOOP can be tested either locally,
or via a modem from a maintenance center. This valuable feature saves time and
money while enhancing overall subscriber satisfaction.
The system supports a sophisticated remote power feeding system. This system
supplies power to the HU and subscriber units, eliminating the need to provide an
external power supply and meter at the HU site. For a more comprehensive
description of the remote power feeding, see “Two-Pair Remote Power Feeding”
on page 9.
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CHAPTER
2
System Configuration
The CTLOOP supports the star topology, in which the CU is connected directly to
more than one HU. Each HU is connected to the CU using the 2W, 784 kbps
digital link.
A star configuration is shown in below.
CTLOOP Star Configuration
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CHAPTER
3
Features
CTLOOP offers a number of features. This chapter describes these features in
detail.
Interfaces
CTLOOP features a wide range of interfacing capabilities on both the exchange
and subscriber sides, as described below.
Exchange Side
The CU can connect to one or more local exchanges. These exchanges can be
either electromechanical (step-by-step or cross-bar) or digital.
CTLOOP uses two types of network termination points to interface with analog
telephone lines.
Subscriber Side
The HU interfaces with subscriber equipment. Each subscriber receives 64 kbps. It
can connect to any combination of the following devices:
• Voice
Pulse and DTMF telephone sets
Pay phones with 12/16 kHz metering signal
Pay phones with polarity reversal
• Data
High speed facsimile machines
High speed 2W modems for computer-generated data
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Features
Advanced Management
The CU enables control of the entire CTLOOP system, including the HU and
subscriber links.
The CU contains two RS-232 ports to enable maintenance as follows:
• one port for connecting the Management Unit (MU), which enables local
control of the CU to which it is connected
• one port for daisy-chaining several CUs located at one site, enabling the
Management Unit (MU) to control all CUs at the site
Power System
CTLOOP's power system offers advanced power supply and management
capabilities. Power system components are located in both the CU and HU.
CU
The CU is powered by a DC power supply module connected to the exchange DC
power supply or any other external source. A DC/DC converter, housed in the
power supply module, converts the incoming voltage into the various voltages
required by the CU.
CU power consumption varies according to the number and type of interface
modules installed in the system.
HU
The HU is powered by either a local power supply, or a remote power feeder
located in the CU site. The power from the remote feeder is fed to the HU through
the trunk link.
Local Power Feeding
CTLOOP supports local power feeding, in which the HU is powered locally from
the 220V/110V AC outlet or from a local 48V DC power supply.
Remote Power Feeding
CTLOOP supports remote power feeding, in which the CU supplies the power
required by the HU and subscriber loops via the trunks.
A remote power feeding supply module at the CU (the RPF module) boosts the
DC input voltage received from the exchange. The boosted voltage is then routed
to the trunk interface cards, which have been specially adapted to handle both AC
signals for telecommunication purposes and DC current for power purposes.
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P/N 762-90100H
CTLOOP System Description
From the trunks, the boosted current runs through the communication links to the
HU. The HU trunk adapters are fitted with a special energy unit (HNRU) which
transforms the boosted DC voltage into the required lower voltage supplies.
RPF output voltage does not exceed ±60 VDC in order to comply with the
international IEC950 safety standard.
Batteries
Optional rechargeable batteries can be installed in the HU, both in the remote and
local feeding operation.
The batteries serve two functions:
• During peak usage hours, when power consumption is greater than power
available from the remote power source, the HU draws on battery power as a
supplement. During off-peak hours, the remote power source supply is used to
recharge the batteries.
• If local or remote power fails, the batteries enable the CTLOOP to provide
service for between four to ten hours, depending on traffic load.
Two-Pair Remote Power Feeding
In addition to normal remote power feeding through the pair used as the trunk
between the CU and HU, remote powering of the HU can be implemented using
two pairs, resulting in higher power at the HU input than when using one pair.
This will enable the use of remote feeding for installations requiring high traffic
loads.
Power Monitoring
CTLOOP includes advanced power management functions. These functions are
accessed and activated locally from the CU, or by modem from the remote
maintenance unit.
Alarms and indications on low input voltage, battery status or power failure are
displayed on the screen, enabling the user complete control over CTLOOP’s
power system.
Backup Pair (Option)
CTLOOP utilizes the second pair, as a backup pair for transmission and power. If
the transmission main pair is disconnected, for any reason, the CTLOOP
automatically switches transmission and the power to the second pair.
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Features
Auto-Recovery
Following a forced shutdown, CTLOOP restarts and recovers automatically. If the
trunk fails CTLOOP periodically sense the faulty trunk every minute. If the fault
on that trunk is cleared CTLOOP automatically recovers the service on that trunk.
Auto-Configuration
CTLOOP's automatic configuration feature enables changing of line interface
modules without the need for any additional hardware or software settings.
CLASS (CLI Support)
CTLOOP supports advanced CLASS services like Caller Line Identification.
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P/N 762-90100H
CHAPTER
4
Functional Description
The CU and HU perform a number of functions in order to transmit and receive
calls and data from the exchange and subscribers. These functions are performed
by line interface and trunk interface modules in the units.
The following figure shows a basic block diagram illustrating the connections
between the CU and HUs, and between the major modules within the units.
CTLOOP Basic Block Diagram
RPF
(REMOTE POWER
FEEDING)
CU and HU Line Interface Modules
The CU and HU line interface modules perform the following functions:
• Coding and decoding - conversion of analog signals to digital code and viceversa according to the A-Law method
• Ring detection (CU only) and ring generation (HU only)
• Testing (HU only)
• Supervision of on/off hook status and dialing
• Impedance, relative level, and echo return loss matching
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Functional Description
•
•
•
•
DC loop change detection (HU only) and regeneration (CU only)
12/16 kHz pulse metering detection (CU only) and regeneration (HU only)
Overvoltage protection
Battery feeding (HU only)
CU Trunk Interface Modules
The CU trunk interface modules perform the following functions:
• Multiplexing of incoming data from the exchange
• Generation of PCM signals to be transmitted over the copper communication
link to the HU
• Duplex transmission and receiving of data to and from the HU in three streams:
data, signal and control.
HU Trunk Interface Modules
The HU trunk interface modules perform the following functions:
• Duplex transmission and receiving of data to and from the CU in three streams:
data, signal, control.
• Demultiplexing of data transmissions from the CU, and transfer to the line
interface module.
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P/N 762-90100H
CHAPTER
5
Modules
CU
The star CU configuration consists of 12 line modules with four trunk modules
serving up to 120 POTS lines through 12 HUs, using 12 HDSL 2W trunk link,
with a transmission rate of 784 kbps.
The CU is available in a 7U cage, with the optional remote power feeding unit in a
separate 2U cage.
The CU modules contain front-access connectors for connecting the subscriber
lines from the exchange's MDF to the CTLOOP.
The Central Unit (CU) contains the following modules:
• Up to four 784 kbps trunk interface modules (CT78)
• Up to 12 line interface modules (PLIC)
• One CPU module (ECPU)
• One DC power supply module (PSDC)
• One optional Remote Power Feeder- (RPF)
CU Cage
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Modules
HU
The Home Unit (HU) is installed in a sealed, waterproof cabinet which can be
mounted on an internal or external wall, attached to a pole or mounted in a street
cabinet.
The HU contains the following modules:
• CPU Module (CPUM)
• Basic Line Interface Module (BLIM)
• Trunk interface module (HT78)
• Subscriber Loop Test Module (SLTM) - Option
• Motherboard and test relays (SBMB)
• HU energy unit (HNRU)
• Battery unit (BATT)
Home Unit (HU)
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P/N 762-90100H
CHAPTER
6
Management and
Maintenance
CTLOOP includes a management unit (MU) which provides advanced
maintenance and testing functions.
Management Unit (MU)
CTLOOP's MU is a tool that enables the user to manage, maintain, and test the
system easily. It comprises a PC with a software package operating under
Microsoft Windows™.
The MU provides the user with the following features:
• Security
• System configuration display
• Alarm and performance monitoring
• Maintenance operations and tests
• Administration setups
The MU security feature prevents unauthorized persons from operating the system
and changing its data and parameters. Users are divided into three classes:
Operator, Service, and Supervisor. Each class can access menus and dialog boxes
specific to that class. Menu items which are not authorized to specific personnel
are displayed in gray.
The software is menu-driven.
The following figure illustrates the MU menu options.
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Management and Maintenance
MU Menu Options
REMOTE LINE
TEST RESULTS
OBJECT
CONFIG
DISCONNECT
REMOTE LINE
TESTS
SYSTEM
CONFIG
CHANGE USER
CLASS
TESTS
MAPPING
CONNECTION
EXIT
ALARMS
SETUP
CHANGE
PASSWORD**
WINDOW
CASCADE
CHANGE
LOCATION**
LOOP BACKS**
ARRANGE
ICONS
THRESHOLDS
SETUP**
LOOP BACKS**
TILE
CHANGE
SYSTEM
NAME**
HELP
INDEX
USING HELP
ABOUT MU
CHANGE
ALARMS
SEVERITY
LEVEL**
* Service Password Level
** Supervisor Password Level
ENABLE
BACKUP PAIR**
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P/N 762-90100H
CTLOOP System Description
The MU enables management of Teledata’s Network Elements (NE’s) from a
local or remote site. Thus eliminating the need to visit installation sites, and
provides rapid fault identification and service provisioning.
The following figure shows an example of the network map menu options.
Network Map Window
The MU can also display the hardware configuration of each system unit,
including types, software versions, and status of the various modules.
The following figure shows an example of the hardware configuration menu
options.
Hardware Configuration Window
Testing is an important MU function. From the Test window, the user can:
• Select a test type from the following list:
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Management and Maintenance
Capacitance
Leakage
Foreign AC voltage
Foreign DC voltage
Noise
VF (Future Option)
• Activate a test
• Abort a test when executing
• Filter test results to display only results of special interest, according to time
intervals, type, line selections, and result type (pass/failed).
The Setup window enables the user to set threshold values used by the MU for
comparison against test results.
General Tests
CTLOOP uses two main methods of testing:
• Self-tests
• User-initiated tests
Self-tests are automatically run on system functions and subscriber lines (e.g. to
test if a specific line is active). Test results are indicated by LEDs on the front of
CU modules and inside the HUs.
User-initiated tests are run by the user through the Management Unit, which is
connected to the CU directly or via a modem through the local exchange. The user
selects a test and is prompted for parameters. Examples of these tests are:
• Trunk status details
• Automatic configuration data regarding the presence or absence of system
modules
Remote Subscriber Loop Tests
In addition to system tests, CTLOOP enables the user to test equipment installed
at subscriber premises. The tests can be run from the MU connected to the CU
directly or via a modem.
Each HU can be equipped with an optional built-in test module, capable of testing
the 10 POTS loops connected to the HU. Tests are activated and results reported
through the CU-HU Embedded Operation Channel (EOC), without the need for an
additional pair of test communication wires. The tests are described in the
following paragraphs.
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CTLOOP System Description
Voice Frequency Test [F]
This test verifies the existence of a Voice Frequency (VF) path in the CU and HU.
Each unit is tested separately.
Loop Tests
The system performs the following loop tests:
• Foreign DC voltage
• Foreign AC voltage
• Capacitance
• Noise
• Leakage
Alarms and Indicators
CTLOOP issues visual and audible alarms at the CU and HU to alert the user to
system problems. LEDs are used to display the visual alarms.
The alarm severity can be set to one of three severity levels: major, minor, and
warning. The severity for each alarm has a default setting that can be changed
from the MU.
System and Object Alarm States are indicated on the screen. The severity of the
alarm is indicated by the following colors:
• Green - Operational
• Yellow - Warning
• Magenta - Minor
• Red - Major
The Alarm menu presents the user with a list of alarms that occurred in the
system. The list can be filtered to include only alarms of interest to the user. The
items which can be filtered are: date, time, alarm type, alarm severity or active
state of the alarm.
When a Major or Minor alarm is activated, the corresponding relays are closed.
An alarm reset push-button is provided to open the alarm relay. This feature is
used mainly during repair activities. The push-button controls the alarm relay
only, and the LED indicators remain on until the alarm is cleared. If a new alarm
is generated after the push-button has been pressed, the relay is operated again.
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Management and Maintenance
Alarm Types
• General failures
Communication Loss to MU
Card Out
Ringer failure
Door open
HU disconnected
• Power failures
Local feeding voltage < Vin min.
or
Remote feeding voltage < Vin min.
Battery voltage is too low
DC/DC output voltage too low or too high
Battery is being discharged
• Trunk failures
Trunk Bit Error Rate
Transmission over backup pair
• Line failures
Short circuit on one or more lines
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P/N 762-90100H
CHAPTER
7
Technical Data
Power Source Requirements
CU
Input Voltage:
Power Consumption:
-40.5 to 72 VDC
98 W max.
HU
Local PS input voltage:
Power consumption:
40.5 to 72 VDC
16 W max.
RPF
Input Voltage:
Power Consumption:
Output Voltage:
-40.5 to 72 VDC
500 W max.
±60 VDC
Mechanical Data
CU
Dimensions:
Weight:
19 inch x 27cm x 6U
15 kg max.
HU
Dimensions:
Weight:
400 x 300 x 150 mm
9 kg max.
RPF
Dimensions:
Weight
P/N 762-90100H
19 inch x 27cm x 2U
5 kg max.
Page 21
Technical Data
Environmental Conditions
Temperature
CU and RPF
Operating
Storage
-10oC to +45oC
-40oC to +70oC
HU
Operating
Storage
-20°C to +55°C
-40°C to +70°C
Relative Humidity
95% (non-condensing)
EMC
Electromagnetic Emission
Susceptibility
ESD
Spikes
EN 55022 Class A
and VDE 0878
IEC 801-2,
IEC 801-3
IEC 801-2
IEC 801-4
Reliability (MTBF)
CU
ECPU
PSDC
CT78-3
PLIC
ELIC
> 10 years
> 15 years
> 10 years
> 10 years
> 10 years
HU
BLIM
CPUM
HT78
HNRU
SLIM
> 10 years
> 20 years
> 12 years
> 10 years
> 15 years
Optional Items
BATT (remote)
Page 22
> 5 years
P/N 762-90100H
CHAPTER
8
Abbreviation and Acronyms
The following abbreviations and acronyms are used in this document:
BA
Basic Access
BLIM
Basic Line Interface Module
CPUM
CPU Module
CT78
CU 784 kbps (line interface module)
CU
Central Unit
DTMF
Dial Tone Multi-Frequency
ECPU
Extended CPU (module)
EOC
Embedded Operation Channel
[F]
Future Option
HDSL
High bit rate Digital Subscriber Line
HNRU
Home unit eNeRgy Unit
HT78
Home uniT 784 kbps (line interface module)
HU
Home Unit
ISDN
Integrated Services Data Network
LE
Local Exchange
MTBF
Mean Time Between Failures
MTTR
Mean Time Till Repair
MU
Management Unit
PLIC
Programmable Line Interface Module
POTS
Plain Old Telephone Service
PSDC
Power Supply DC (module)
RPCU
Remote Power Central Unit
SLTM
Subscriber Loop Test Module
VF
Voice Frequency
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