2-16. SELF-TEST. Continued
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 Test (FAIL5). The TEST signal is routed to the COMSEC module. The COMSEC module re-
sponds with the FAULT 5-P signal. The signal is buffered by the fill routing module and sent to the control module.
This signal should remain at logic 1 during self-test or "FAIL5" will be displayed.
g. SNAP Test (FAIL6). The TEST signal is routed to the SYSTEM connector. The RT is capable of interpret-
ing a self-test response from external SNAP equipment, A failure response at the SYSTEM connector is indicated
by a "FAIL6" display. See paragraph 2-21.
h. Fill Routing Test (FAIL7). The TEST signal is routed to the fill routing module (1A15). This module
performs its own self-test which checks the RAM, ROM, and the fill I/O bus. The control module is informed over
FR OUT, the asynchronous serial interface link.
If the fill routing module fails self-test, "FAIL7" is displayed.
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
ICOM I/O section.
This 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
During cipher text operation, the operator of the retransmit station can monitor the traffic if an RT-1523(C)/U is
used, An RT-1523(C)/U is not required for operation of the retransmit station.
2-18. FILL OPERATION.
The ECCM module requires electronic data for FH operation. The data is in the form of TRANSEC keys, hopsets,
and lockout sets. The process of providing the data is called the fill operation. It can be performed two ways. All
data can be loaded locally using the RT AUD/FILL connector. The second method is the ECCM remote fill (ERF).
It can only be used for hopsets and lockout sets. ERF is relatively automatic.
The ECCM module adds a
preamble to the transmitted data that identifies it as fill data. The ECCM module in the receiving RT detects the
preamble and stores the data in holding memory.
The COMSEC module requires electronic data for CT operation. This data consists of COMSEC variables loaded
through the AUD/FILL connector by fill device.
All fill data loaded through the AUD/FILL connector is processed by the fill routing module (1A15). The following
signals are passed between the fill routing module and the fill device.