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TM 11-5820-890-30-5
2-16. SELF-TEST. Continued
The audio present during the “88888” display is a result of the receive tests. There are 10 short bursts of
unsquelched rushing noise which can be heard in the handset. However, because they are so quick and close
together, they are difficult to count. At the end of a successful self-test a beep can be heard in the handset.
c. Data Rate Adapter Test (FAIL2). The data rate adapter will perform a self-test when the TEST line is set
to logic 1. It also requires the RCV CLK and 192-kHz CLK signal to perform self-test. If the data rate adapter
passes self-test, then the DATA MODE STATUS line is set to logic 1. If it does not, the line stays at logic 0 and
“FAIL2” will be displayed.
d. ECCM Module Test (FAIL3). The ECCM module also performs an independent self-test. It checks the
ECCM module’s RAM, ROM, interleave, linear sequence generator, and other circuits. If it does not pass
self-test, “FAIL3” will be displayed.
e. Remote Operation Test (FAIL4). The remote operation test checks the remote I/O module and the
two-wire interface. It is performed separate from the above tests. The test is initiated when the FCTN switch is set
to REM and the BATT/CALL key and PTT switch are pressed. If the test is passed, “CALL” will be displayed. If it is
not, “FAIL4” will be displayed.
f. COMSEC and SNAP Tests (FAIL5 and FAIL6). The TEST signal is also routed to the COMSEC connector
and the SYSTEM connector. The RT is capable of interpreting a self-test failure response from external equip-
ment connected to either connector. A failure response at the COMSEC connector will be indicated by a "FAIL5"
display. (Most COMSEC devices, such as the TSEC/KY-57, cannot use this capability. ) A failure response at the
SYSTEM connector will be indicated by a “FAIL6” display. See paragraph 2-21.
2-17. RETRANSMIT OPERATION.
The retransmit (RXMT) function allows two RTs to be used as a radio relay. The only additional equipment
required is a special cable. (See figure FO-9. It is not pin-to-pin.)
When the FCTN switch is set to RXMT, the RT operates as in SQ ON. The main difference is the use of the RXMT
connector for keying and audio input/output. The switching module controls retransmit operation. See figure
FO-9. The receiving RT demodulates the RF as described in paragraph 2-8. The signal is routed to pin B of the
RXMT connector (RXMT SIG OUT). The switching module sets the RXMT CONTROL OUT line to logic 0 when a
signal is received.
The cable that connects the two RTs routes the receiving RT OUT lines to the transmitting RT IN lines. When the
RXMT CONT IN line is at logic 0, the RT is keyed. The RXMT SIG IN is routed through the switching module to the
audio/data section. The audio/data section processes the signal and routes it to the exciter/power amplifier.
Pin F of the RXMT connector is used to select the analog or digital mode. The analog mode is selected if it is open
(about 2.5 V). The digital mode is selected if it is grounded.
During FH operation, the received signal is deinterleaved and the digital data stream is routed to the RXMT
connector.
During cipher text operation, the operator of the retransmit station can monitor the traffic if a COMSEC device is
properly installed. A COMSEC device is not required for operation of the retransmit station.
2-21
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