57
Condition: Cable length between the Distributor and the TS-905 Infrared transmitter/receiver unit is assumed
to be 50 meters.
Central unit
Infrared Transmitter/Receiver units
TS-905
Distributor
L
L1
50 m
18.2.2. Example 2: When installing 4 TS-905 infrared transmitter/receiver units using 1 coaxial cable
reaching from the central unit (one 4-branch distributor connected):
1) Finding the maximum cable length using maximum allowable cable losses
Assuming that RG-59/U coaxial cable is used between the Distributor and the Infrared transmitter/receiver
unit, the cable loss between the two is calculated by the following equation:
Cable loss = 3.3 dB x (50 m / 100 m) = 1.65 dB
Since the Distributor's internal loss is 8.5 dB, the maximum allowable loss between the Central unit and the
Distributor becomes 9.85 dB (20 dB – 1.65 dB – 8.5 dB).
When RG-6/U coaxial cable is used between the Central unit and the Distributor, the length L1 between the
two is,
L1 = (Coaxial cable loss / its cable loss per 100 m )
= (9.85 dB / 2.7 dB) x 100 m
= 364 m
Maximum cable length L between the Central unit and the Infrared transmitter/receiver unit is calculated
by the following equation:
L = L1 + 50 m
= 364 m + 50 m
= 414 m
Similarly calculated for other types of coaxial cables, the maximum cable length between the Central unit
and the Infrared transmitter/receiver unit is found in the following table.
RG-59/U
348 m
RG-6/U
414 m
RG-11/U
542 m
