Design Examples; Example 1: When Installing 4 Ts-905 Infrared Transmitter/Receiver Units Using 4 Coaxial Cables Reaching From The Central Unit - Toa TS-800 Series Operating Instructions Manual

15.3. Design Examples

15.3.1. Example 1: When installing 4 TS-905 Infrared Transmitter/Receiver units using 4 coaxial cables
reaching from the Central unit:
Central unit
1) Finding the maximum cable length using maximum allowable cable losses
Assuming that the type of coaxial cable used is RG-59/U,
Maximum cable length L = (Coaxial cable loss / its cable loss per 100 m )
The following table shows the maximum allowable cable length for each type of coaxial cable.
RG-59/U 606 m
RG-6/U 740 m
RG-11/U 1000 m
2) Finding the maximum cable length using voltage drop
Since one TS-905 Infrared Transmitter/Receiver unit is connected per coaxial cable, the current that flows
through each coaxial cable is 0.1 A.
Assuming that the type of coaxial cable used is RG-59/U,
Maximum length L = { (Voltage drop 1 / Current 1) / Coaxial cable loop resistance 1 for 100 m }
The following table shows the maximum allowable cable length for each type of coaxial cable.
RG-59/U 297 m
RG-6/U 390 m
RG-11/U 2083 m
The table below shows the required maximum cable length for the example 1, the shorter length of the
calculation results (1) and (2) above.
RG-59/U 297 m
RG-6/U 390 m
RG-11/U 1000 m
L
= (20 dB / 3.3 dB) x 100 m
= 606 m
= { (5 V / 0.1 A) / 16.82 Ω } x 100 m
= 297 m
Infrared Transmitter/Receiver units
TS-905
47