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TECH
CORNER
HDMI Cable Quality
Matters in Pro AV
By Ron Justice,
Director of Technical Services
But the typical home AV system
intended for entertainment is not the
and strain reliefs, and how they’re all
same as a custom-designed, fully
put together, are equal contributors to
integrated conference room, boardroom,
cable performance. And even if they’re
or classroom that’s essential to the
purchased from well-known, established
productivity or institutional mission of
brands, low-cost or seemingly “bargain”
an organization. In these environments,
cables are not immune from quality
signal integrity and system reliability go
issues. In practice, these cables may not
hand in hand. Saving a few dollars with
save you any money at all.
bargain cables, against a total AV system
cost of perhaps $25,000 to $50,000
T
cable, connectors, termination, moldings
or more, is simply bad economics. In
Cables Can Damage Your Equipment
A few months ago, we began
here’s a popular belief, widely tossed
commercial AV, you truly do “get what
hearing about HDMI connector failures
around on the Internet, that all HDMI
you pay for,” and cables can be the
on competitors’ products. About the
cables are the same. If there’s a picture
determining factor in whether or not
same time, calls starting coming in
at the end of the cable, it’s impossible
the system works.
on our technical support line about
to tell the difference between a cheap
cable and one that costs two or three or
ten times as much. I suppose that’s a
There’s more to an HDMI cable, for
that matter any pre-terminated cable,
than just the wire from which
intermittent performance and damaged
HDMI input/output connectors on our
DXP HDMI and SMX HDMI Series digital
fair statement if one is connecting
it’s constructed.
matrix switchers. What was puzzling is
a $99 Blu-ray player to a $500 flat
The quality
that we’ve shipped thousands of these
panel purchased from the local
of the raw
switchers over the past couple of years
discount warehouse. In the typical,
without any mechanical issues, and
simple home entertainment
nothing’s changed on our bill of materials
system, the source
in regard to the HDMI connectors that
and display are rarely
we use. Connector damage is highly
more than a few feet
unusual with Extron switchers, and
apart. If the signal is
the number and frequency of these
occasionally intermittent,
complaints merited a full investigation.
the system can usually be
We take issues such as this to heart: we
“fixed” with a little judicious
want to get the products repaired and
wiggling of cables.
back into service as quickly as possible,
but we also need to determine the root
cause of the problem so that we can
advise our customers on preventative
actions. Further troubling, but hinting
toward an underlying cause, was the
fact that the repaired switchers were
exhibiting the same problems after they
were reinstalled by the customer.
As our technical support team began
digging into the issue, we found a
commonality among these failures – in all
cases, the HDMI cables in use were from
one popular, on-line supplier of low-price
cables. When we put these cables under
the microscope, we discovered that
some cables had connectors that were
damaged in manufacturing, and others
Tech Corner
AV SYSTEMS DESIGN Summer 2012
TECH CORNER
optimum conductivity and corrosion
HDMI connector, damaged by a faulty cable; pins
are lifted or pushed back, resulting in intermittent
or lost signals.
There is a cost to terminating cables in
resistance. We sell products worldwide
this fashion, but we feel that it’s the best
for installations in virtually every type
way to ensure signal integrity within a
of climate. We want to be confident
complex AV system design.
that our cables will work equally well
Next, wire gauge is an important
whether ambient conditions are dry
contributor to signal integrity, particularly
or humid, or where there’s a high salt
as cables grow in length, although
content in the air as is typical in many
advances in technology are helping to
coastal environments.
increase performance with smaller gauge
How the connector and wires are
wires. Rather than take a “one AWG
terminated is absolutely critical to overall
fits all” approach, we offer a range of
cable performance, and this is an area in
high quality, high performance cables
which many manufacturers take shortcuts
that fit specific integration needs. For
in order to meet cost targets. In the
connections between devices within
Extron HDMI Pro Series cable, notice
the rack, we have the MDC HDMI
had a particular HDMI connector design
that all of the signal grounds are tied
Series MicroDigital cables in 36 AWG,
that causes pins in the switcher I/O
together, and then tied to the connector
and the HDMI Ultra Flex Series cables
connectors to be lifted or pushed back,
shell. This provides better grounding
in 30 AWG. These lightweight, highly
resulting in intermittent or lost signals
and better EMI immunity, helping to
flexible cables are available in lengths
and “fatal” damage to the I/O ports.
protect the HDMI signal from external
from 1.5 to 15 feet, and were created
When repaired switchers are reinstalled
interference. We use this same technique
in response to integrator requests for
with Extron HDMI cables or those from
in our other HDMI cable lines as well.
high performance cables that could be
a different manufacturer, no additional
damage occurs and the switchers work
as expected.
Given our recent experience, I think
it’s safe to say at this point that all
Anatomy of High Quality HDMI Cable:
Extron HDMI Pro Series
HDMI cables are not the same. As I
mentioned earlier, a cable is more than
just wire. Extron HDMI cables are built to
our specifications, starting with the bare
wire. All attributes of the cable – the wire
gauge of the conductors, jacket material,
construction, connectors, molding
Gold-plated contacts and
connector shell for
exceptional conductivity
and corrosion resistance
Solder Braid
Inner Mold
Foil Shield
Conductor wire gauge is optimized by
cable length for superior performance
and strain relief – are made to Extron
specification. How the cable is designed
and manufactured has a huge effect on
its performance in an AV system. Often,
it’s the details that help to separate a
Continuous connection between Connector Shell,
Solder Braid, and Foil Shield provides maximum
rejection of EMI/RFI interference to maintain signal
integrity throughout the length of the cable
merely-functional cable from one that
you can rely upon for critical AV system
performance, day in and day out.
It’s What’s Inside That Counts
Let’s take a look inside an Extron
HDMI Pro Series cable and I’ll show
you what I mean. First, we start with
a very high-quality HDMI connector,
Molded Strain Relief provides 360°
bend radius, reducing cable stress
for long-term reliability
TMDS signal grounds are tied together
for improved grounding and additional
EMI immunity
with gold-plated contacts and shell for
www.avsystemsdesign.com
Tech Corner
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TECH CORNER
easily and neatly dressed within the rack.
always fairly priced, manufactured to
another time at which the meeting can
For longer cable runs, from the rack to
be rescheduled. A lost client is worth
our exacting standards, and backed by
the display, for example, our HDMI Pro
far more than the few dollars saved
the Extron 100% Satisfaction Guarantee.
Series is available in two wire gauges:
on cables.
And when you do install them, you can
24 AWG for lengths up to 12 feet, and a
As I said at the outset, in commercial
be confident that Extron cables will work
heavier 22 AWG for lengths from 12 feet
AV, you get what you pay for. When
as advertised for the life of the project,
up to 200 feet.
asked, we will always recommend
with the quality and performance you’ve
come to expect from all Extron products.
Finally, all Extron cables are fully
that you use Extron HDMI cables for
tested and run through a rigorous QA
your AV system installation. While our
process before delivery. We take the
HDMI cables will likely never be the
same conservative approach with cable
lowest-priced on the market, they’re
Ron Justice is Director of Technical Services for
Extron Electronics.
specifications that we do with specs
for our powered products. Rather than
simply say “meets HDMI High Speed
Extron HDMI Cables
specifications” or “exceeds HDMI
Standard Speed specifications” and
assume that the average customer
knows what those terms mean, we
clearly spell out the tested performance
criteria that a particular cable, or cable
HDMI Pro
length, meets or exceeds – data rate,
resolution, refresh rate, color bit depth,
and at what length an external cable
HDMI Ultra
equalizer is needed. We think it’s
important to provide cable performance
criteria up front, so that you can make
an informed purchase decision before
MDC HDMI
the installation begins.
Making the Right Choice: Why
Cable Quality Matters
At its core, your choice of cables
for an AV system installation ultimately
comes down to the intended use of the
system and its importance to the day
to day needs of the client. If your home
entertainment system, for example, fails
just before the big game because of
a bad cable, it’s upsetting and you’re
disappointed, but life goes on – you
can catch the game at a neighbor’s
house or a local sports bar, or watch
it online. If a bad cable causes the
boardroom AV system to fail in front of
your client’s CEO and other senior staff,
there’s likely hundreds if not thousands
Wire gauge is an important contributor to signal integrity, particularly as cables grow in length. Rather
than take a “one AWG fits all” approach, Extron offers a range of high quality, high performance
cables that fit specific integration needs. The Extron MDC HDMI MicroDigital Series and HDMI Ultra
Flex Series of lightweight, ultra-flexible cables are available in lengths up to 15 feet, and are ideal for
interconnection of devices within a rack, or for use within a Cable Cubby or TLP TouchLink Cable
Cubby enclosure. For longer cable runs, from the rack to the display, for example, Extron HDMI Pro
Series is available in two wire gauges: 24 AWG for lengths up to 12 feet, and a heavier 22 AWG for
lengths from 25 feet up to 200 feet. An Extron HDMI 101 Plus Cable Equalizer is recommended for
use with cables longer than 75 feet.
AWG
Lengths (in feet)
HDMI Spec
Max. Data
Rate
Resolution Supported
MDC HDMI
36
1.5, 3
High Speed
10.2 Gbps
1920×1080 @ 60 Hz,
16-bit color
MDC HDMI
36
6
Standard Speed
4.95 Gbps
1920×1080 @ 60 Hz,
8-bit color
HDMI Ultra
30
6, 9, 12, 15
High Speed
10.2 Gbps
1920×1080 @ 60 Hz,
16-bit color
HDMI Pro
24
3, 6, 12
High Speed
10.2 Gbps
1920×1080 @ 60 Hz,
16-bit color
HDMI Pro
22
25, 35, 50, 75, 100,
125, 150, 175, 200
Standard Speed
4.95 Gbps
1920×1080 @ 60 Hz,
8-bit color
Series
of dollars worth of productivity on the
line – there may not be another room
Please visit www.extron.com/hdmicables for more info.
available with the same capabilities, or
Tech Corner
AV SYSTEMS DESIGN Summer 2012