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TM 11-5820-890-30-5
2-13. TRANSMIT DATA SIGNAL PATH. Continued
In the FH mode, the BS DATA signal in the switching module is sent to the ECCM module for interleaving. The FH
DATA signal is returned to the switching module to continue the data signal path.
In the cipher text mode, the DIGITAL DATA signal in the audio control module is routed to the COMSEC
connector. The COMSEC device encrypts the signals and returns the VIN CT XMT signal.
The digital data clock out (DDCO) originates in the switching module (PT DIGITAL CLK-R), the COMSEC device
(CT DIGITAL CLK), or the data rate adapter section (LO SPD CLK).
2-14. PRIMARY CONTROL SIGNALS.
The primary control signals originate at the front panel. They direct the operation of the RT. The connectors,
switches, controls, and circuitry on the front panel are connected to the parent board through three connectors.
They are the front panel switches connector (J1), the display connector (J2), and the audio/data connector
(J3). See figure FO-7.
The function of the radio is controlled by the FCTN switch. When it is set to OFF, primary power is removed from
the RT. The switch position is checked by the control module. If the switch is set to TST, SQ OFF, RXMT, REM,
LD, LD-V, or Z-A, the corresponding line to the control module is set to logic 1 by the switch. If none of these
lines are at logic 1, the control module sets the RT for SQ ON operation.
Primary power (PRI 13 V DC) for the RT is also routed through the FCTN switch. Primary power must be provided
at either pin L of the system connector (P1). The 13 V DC will be applied to the SWITCHED 13 V DC line when the
FCTN switch is at any position other than OFF or STW. The SWITCHED 13 V DC provides the input voltage for the
power supply (1A3 pins B and C). If the FCTN switch is set to OFF, the 13 V DC will be applied to the OFF 13 V DC
line. Both SWITCHED 13 V DC and OFF 13 V DC lines are routed to the display CCA where they are used to power
the PRI BTRY PRES and V HOLD lines.
Two voltages are available to retain the fill information in the control module and the ECCM module. They are V
BATT and V HOLD. V BATT is provided by the holding battery and is routed through the FCTN switch. V HOLD is
provided by the display CCA. It is derived from the primary input voltage. If both are present, V HOLD will be used
instead of V BATT. Both are turned off when the FCTN switch is set to STW.
The control module also checks the MODE, CHAN, and RF switch positions. The control module sets the MODE
SW COM line to logic 1 except during remote operation. The control module checks the FH and FH/M lines. If
neither is at logic 1, the RT is set for SC operation. The CHAN switch is BCD encoded as follows:
CHAN
PRESET 0
PRESET 1
PRESET 2
MAN
1
2
3
4
5
6
CUE
0
1
0
1
0
1
0
1
0
0
1
1
0
0
1
1
0
0
0
0
1
1
1
1
2-17
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