RECEIVER SWITCHBOARD

programming feature that can store up to 100 preprogrammed frequencies. A keypad is used to key in frequencies either for use or program storage. The receiver may scan any or all of the preprogrammed frequencies to check for traffic on the frequency. Operator maintenance is limited to scheduled cleaning, visual inspection, and initiating a periodic self-test routine. No special training or equipment is required. The front panel should be checked once a day for display of a fault condition to ensure that there is no internal circuitry failure. Details of these operator maintenance procedures, as well as easy to follow operator instructions, are contained in Technical Manual Operation and Maintenance Instructions with Parts List, Receiver R-2368/URR, EE125-FC-OMI- 010/R-2368/URR. RECEIVER SWITCHBOARD The receiver transfer switchboard allows you to transfer the audio output from the receivers to remote control station audio circuits. Figure 1-24 shows two representative SB-973/SRT receiver transfer switchboards. These switchboards contain ten 7-posi- tion switches. Each switch is connected to a remote station, such as a facsimile recorder, the TESS input jack, or an audio speaker. Each of switch positions 1 through 5 relates to a receiver, which is usually specified on an engraved plate along the top of the switch case. In figure 1-24, only the first four switches of each switchboard have been used, as seen by the engraved equipment identification adjacent to each switch. The position "x" on each switch allows you to transfer the circuits to additional switchboards. AN/URA-17 COMPARATOR-CONVERTER A comparator-converter device is used to convert a radio receiver’s frequency shift keying audio output carrying radioteletype information into direct current (dc) pulses compatible with a teleprinter. The comparator-converters currently used aboard Navy ships are the AN/URA-17(B) or (C) versions (fig. 1-25). A group consists of two CV-483/URA-17 frequency shift converters cross connected with a wiring harness. The output of each CV-483 is hardwired into receiver transfer switchboards, and usually identified as URA-17 "A" for the top converter, and as AN/URA-17 "B" for the bottom unit. Two converters are supplied so that the user may tune in the same radioteletype broadcast on two separate frequencies with two radio receivers, and feed the output from both converters into the same printer. This method of copying a radioteletype broadcast is Figure 1-24.—SB-973/SRT receiver transfer switchboards. l-40