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QuickMedia™ Distribution Amplifier Crestron QM-DA
The aggregate cable length of a signal path originating at a QM transmitter and
terminating at a QM receiver must not exceed 450 feet (137 meters). Video signals
may experience a loss of quality over very long lengths of cable. This phenomenon is
due to the added resistance and capacitance of longer cable lengths and is not
peculiar to either Crestron and/or QuickMedia systems. To ensure sufficient
bandwidth, the maximum aggregate cable length should not exceed 450 feet. The use
of lower-resolution signals may allow increased cable length but must be tested by
the installer with the sources to be used. The QM pin assignment is based on the
EIA/TIA 568B RJ-45 Jack standard.
NOTE: When transmitting S-video, luminance uses the green video pathway and
chrominance uses the red video pathway. When transmitting composite video, the
signal is carried on the blue video pathway.
NOTE: When using CresCAT-QM wiring, four additional wires are included for
making Cresnet connections.
When connecting multiple QM devices, the route between a QM origination point
(transmitter) and a QM endpoint (receiver) cannot have more than two midpoints
(e.g. QM-MD7x2 or other QM switchers). Refer to the following diagram when
configuring a QM network.
NOTE: The aggregate length from transmitter to receiver cannot have a delay skew
or more than 22 ns.
QM Network Topology
TPS-12G/15G-QM-L
QM-TX
QM
QM
QM
QM
Origination Points Endpoints
QM
Midpoints
QM-FTDC
QM-DAQM-MD7x2
TPS-12G/15G-QM-L
Installation
Ventilation
The QM-DA should be used in a well-ventilated area. The venting holes should not
be obstructed under any circumstances.
To prevent overheating, do not operate this product in an area that exceeds the
environmental temperature range listed in the table of specifications. Consider using
forced air ventilation and/or incrementing the spacing between units to reduce
overheating. Consideration must be given if installed in a closed or multi-unit rack
assembly since the operating ambient temperature of the rack environment may be
greater than the room ambient temperature. Contact with thermal insulating materials
should be avoided on all sides of the unit.
Rack Mounting
The QM-DA can be mounted in a rack or stacked with other equipment. Two “ears”
are provided with the QM-DA so that the unit can be rack mounted. These ears must
be installed prior to mounting. Complete the following procedure to attach the ears
to the unit. The only tool required is a #2 Phillips screwdriver.
8 • QuickMedia™ Distribution Amplifier: QM-DA Operations Guide – DOC. 6547A