Crestron
QM-MD7x2
QuickMedia™ Matrix Switcher/Mixer
power factor of the entire chain. The length of the run in feet and the power factor of
the run should be used in the following resistance equation to calculate the value on
the right side of the equation.
Resistance Equation
R = Resistance (refer to table below).
L = Length of run (or chain) in feet.
PF = Power factor of entire run (or chain).
R < L x PF
40,000
Where:
The required wire gauge should be chosen such that the resistance value is less than
the value calculated in the resistance equation. Refer to the table after this paragraph.
Wire Gauge Values
RESISTANCE (R)
WIRE GAUGE
4
16
6
18
10
20
15
22
13
Doubled CAT5
8.7
Tripled CAT5
NOTE:
All network wiring must consist of two twisted pairs. One twisted pair is
the +24V conductor and the GND conductor. The other twisted pair is the Y and Z
conductors.
NOTE:
When daisy-chaining Cresnet units, strip the ends of the wires carefully to
avoid nicking the conductors. Twist together the ends of the wires that share a pin on
the network connector, and tin the twisted connection. Apply solder only to the ends
of the twisted wires. Avoid tinning too far up the wires or the end becomes brittle.
Insert the tinned connection into the Cresnet connector and tighten the retaining
screw. Repeat the procedure for the other three conductors.
NOTE:
For larger networks (i.e., greater than 28 network devices), it may become
necessary to add a Cresnet Hub/Repeater (CNXHUB) or Cresnet Network Poll
Accelerator (C2N-NPA8) to maintain signal quality throughout the network. Also,
for networks with lengthy cable runs, it may be necessary to add a Hub/Repeater
after only 20 devices.
QuickMedia Wiring
The Crestron QuickMedia cable (sold under the name “Crescat-QM”) contains one
CAT5E cable and one Cresnet cable in siamese jackets. Installation of any QM
device is as simple as installing one set of QM wires from the output of one device to
the input of another. Installations are flexible, affordable, and fast.
Operations Guide - DOC. 6273
QuickMedia™ Matrix Switcher/Mixer: QM-MD7x2
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