Example 4: When Installing 16 Ts-905 Infrared Transmitter/Receiver Units; Using 1 Coaxial Cable Reaching From The Central Unit (Five 4-Branch Distributors Connected) - Toa TS-800 Series Operating Instructions Manual

15.3.4. Example 4: When installing 16 TS-905 Infrared Transmitter/Receiver units using 1 coaxial cable
reaching from the Central unit (five 4-branch distributors connected):
Condition: Length between the Distributor 2 and the TS-905 Infrared Transmitter/Receiver unit is assumed to
be 50 meters, and the length between Distributor 1 and Distributor 2 10 meters.
Central unit
1) Finding the maximum length using maximum allowable cable losses
Assuming that RG-59/U coaxial cable is used, the cable loss between the Distributor 2 and the Infrared
Transmitter/Receiver unit is calculated by the following equation:
Cable loss = 3.3 dB x (50 m / 100 m) = 1.65 dB
Assuming that RG-6/U coaxial cable is used, the cable loss between the Distributor 1 and Distributor 2 is
calculated by the following equation:
Cable loss = 2.7 dB x (10 m / 100 m) = 0.27 dB
Because of the 2 serially-connected 4-branch distributors, their loss is 17 dB (8.5 dB + 8.5 dB), which is
added to the above cable loss, causing a total loss of 18.92 dB (1.65 dB + 0.27 dB + 17 dB). Therefore, the
maximum allowable cable loss between the Central unit and the Distributor 1 is calculated to be 1.08 dB
(20 dB – 18.92 dB).
• Assuming that RG-11/U coaxial cable is used, L1 between the Central unit and the Distributor 1 is
calculated by the following equation:
L1 = (Coaxial cable loss / its cable loss per 100 m)
= (1.08 dB / 2 dB) x 100 m
= 54 m
Maximum cable length L (Length between the Central unit and the Infrared Transmitter/Receiver unit)
= 54 m + 10 m + 50 m = 114 m
• Assuming that RG-6/U coaxial cable is used, L1 between the Central unit and the Distributor 1 is
calculated by the following equation:
L1 = (Coaxial cable loss / its cable loss per 100 m)
= (1.08 dB / 2.7 dB) x 100 m
= 40 m
Maximum cable length L (Length between the Central unit and the Infrared Transmitter/Receiver unit)
= 40 m + 10 m + 50 m = 100 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 table.
Distributor 2
Distributor 1
1
L1
10 m
Infrared Transmitter/Receiver units
2
5
50 m
L
TS-905
RG-59/U 92 m
RG-6/U 100 m
RG-11/U 114 m
51