b. 12-Channe l PCM Radio Terminal. In this application the radio set transmits and
receives up to 12 telephone channels and an order wire signal at the same time on a common FM
carrier. The receiver and transmitter operate at the same time on SEPARATE frequencies.
(1) Most of the cabling connections between transmitter, receiver, and order wire are
made at the rear of each component. The cable assemblies used to make these connections are
furnished as part of the AN/GRC-103.
(2) Figure 1 shows how each of the AN/GRC-103 components is connected to the
other. The connection points on each component are labeled as they are in Figure 1. Cables
identified as 1 and 2 are connected to the front panel of the transmitter and receiver. The
remaining cables are connected to the rear of each component. The multiplexer, shown in Figure
1, combines up to 12 telephone input channels into a PCM signal which is input to the
transmitter. It also converts the incoming PCM to its original 12 separate channels.
Become familiar with the location of this figure on your job aid card.