Equipment Highlights: Radio Interface Units

摘要

The Radio Interface Unit (RIU) and its predecessor, the Special Radio Interface (SRI), were developed to provide regulated power to operate various types of foreign radio systems and to provide an interface between the radio's microphone input and headset output, allowing the radio to be operated with standard domestic headsets and microphones. The RIUs also provide an interface that allows communications to be recorded on a standard audio tape recoder. In addition, most types of RIUs allow the operator to monitor the relative volume units (VU) of the received and transmitted audio via a front panel light-emitting diode (LED), bar graph VU meter. The RIUs and SRI provide operational flexibility through the use of a main printed circuit board (PCB) that contains amplification and switching circuitry and small secondary ( daughter ) PCBs, each designed for a particular radio system, that plug into the main PCB. The secondary PCBs ensure proper interface characteristics for the radio system in use. The RIUs and SRI operate off standard 110-Vac, 50/60-hz line voltage: some RIUs may be operated off an external 24-VDC source. The foreign radio systems supported by the SRI and various RIUs include: R-105D, R-107, R-123, R-405, R-802G, R-105M, R-118, R-130, R-407, and R-832. (RH)