54
18. APPENDIX (INFRARED TRANSMITTER/RECEIVER CONNECTION)
This chapter describes how to find the maximum cable length between the Central unit and the Infrared
transmitter/receiver unit.
Values calculated here are given only as guidelines, since they can vary depending on ambient building
conditions and the Infrared transmitter/receiver unit.
18.1. Wiring Design
18.1.1. Confirming the wiring design
To obtain the maximum cable length between the Infrared transmitter/receiver unit and the Central unit,
calculate the cable length on the following each condition. The shorter length of the two results is the required
extendable length.
Values necessary for each calculation are as follows.
• Values necessary for calculating the loss
(1) 2-branch distributor (YW-1022) loss: 4.5 dB
(2) 4-branch distributor (YW-1024) loss: 8.5 dB
(3) Coaxial cable loss per 100 m (table shown below)
Note: The values in the table above are losses at 10 MHz.
• Values necessary for calculating the voltage drop
(1) Operating current per Infrared transmitter/receiver unit: 0.1 A (TS-905), 0.13 A (TS-907)
(2) Distributor resistance loss:
0 Ω
(3) Coaxial cable loop resistance per 100 m (table shown below)
Note: The values in the table above are losses at 10 MHz.
Note: Coaxial cable loss and loop resistance values used here are based on our investigation.
(1) Maximum allowable wiring loss:
20 dB (Total cable and distributor loss)
(2) Maximum allowable DC voltage drop: 5 V
RG-59/U
3.3 dB
RG-6/U
2.7 dB
RG-11/U
2.0 dB
RG-59/U
16.82 Ω
RG-6/U
12.82 Ω
RG-11/U
2.4 Ω
