Toa TS-800 Series - Manual (Page 48)

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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
15.3.2. 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