Digital Data Combiner 1A12 Cable-To-Radio Circuits Functional Block Diagram Description

TM 11-5820-695-35

zero. The CABLE TO RADIO MODEM indicator is

(4) Functional Failure. If any functional

lighted red.

failure exists, A8B has at least one input which is low. If

a cable traffic failure occurs, all inputs to A8B except the

(b) NOR gate A7C receives a low

input from A9D are low. In either case, A8B applies a

from A7B and its output is high (see (5)(b) above). The

high (logic one) to A7B.

high from A7C is inverted to low by A7D and applied to

A8A (para 2-6h).

(5) Cable Traffic Normal-No Functional

Failure. When cable traffic is normal and there is no

functional failure, the conditions of (1) and (3) above

and Q10, Q11, 1CTFL and OCTFL are as explained in

exist and operation is as follows.

(5)(c) above. The traffic in indicator is still lighted

green.

(a) The inputs to A7B are low from

A8B and high from A6A. The output of A7B is then

(7) Cable Traffic Failure. When a cable

high, and as a result, lamp driver Q9 is turned on and

traffic failure occurs (loss of the XCPCM signal), all

output signal 1CFFL is logic zero. The output of A7B,

functional failure signals are also affected and change to

inverted to a low by A6D, turns off lamp driver Q8 and

logic one (high). The conditions of (2) and (4) above

output signal OCFFL is logic one. The CABLE TO

then exist and operation is as follows:

RADIO MODEM indicator is lighted green.

(a) The inputs to A7B are high from

(b) The output of NOR gate A7C is

A8B and low from A6A. The output of A7B is high and

applied to NAND gate A2B. The logic action at A7D

operation is as explained in (5)(a) above.

depends on the operating mode in use. When Radio

Set AN/GRC-144 is being used in radio repeater mode,

(b) NOR gate A7C receives a low

the cable-to-radio circuits of digital data modem 1A12

from A6A and its output is high. The high output from

are not used and signal ORRM is logic zero. The output

A7C is inverted to low by A7D and applied to A8A (para

of A7D is then always high because it is inhibited by the

2-6h).

logic zero (ORRM) at pin 13. This prevents erroneous

application of a. cable-to-radio fault indication to NOR

gate A8A when in radio repeater mode. When Radio

driver Q10 is turned off and output signal 1CTFL is logic

Set AN/GRC-144 is being used in the cable terminal

one. The low from A6A is inverted to high by A6B; lamp

mode, signal ORRM is logic one. NAND gate A7D then

driver Q11 is turned on and output signal OCTFL is logic

has logic one at pin 13 and it acts as an inverter for the

zero. The traffic indicator is lighted red.

signal at pin 12. When a functional failure occurs, NOR

gate A7C has high inputs from A7B and A6A and it

2-5.1 Digital Data Combiner 1A12 Cable-To-Radio

applies a logic zero (low) to A7D. The low is inverted to

high by A7D and applied to NOR gate A8A. This is the

Circuits Functional Block Diagram Description

summary alarm output signal for cable-to-radio circuits

(para 26h).

The functional relationships between cable-to-radio

plug-in components and chassis circuits of digital data

combiner 1A12 are shown in figure 5-8.2. Each plug-in

driver Q10 is turned on and output signal 1CTFL is logic

component is functionalized and the main signal paths

zero. The high from A6A is inverted to low by A6B,

(heavy lines) are shown in figure 5-8.2, as well as

lamp driver Q11 is turned off and output signal OCTFL

control and alarm functions.

is logic one. The traffic in indicator is lighted green.

Digital Orderwire Multiplexer 1A12A1 (fig.

(6) Cable Traffic Normal Functional

5-8.2 and 5-38.3). Digital orderwire multiplexer 1A12A1

Failure. When cable traffic is normal and there is a

is used only when operating in digital orderwire mode. A

functional failure, the conditions of (1) and (4) above

control signal from OW SEL switch 1A12S1 enables it

exist and operation is as follows:

for digital orderwire and inhibits it for analog orderwire.

Input signals to module A1 are digital orderwire signals

(a) The inputs to A7B, from both

from the OCU: 1) 16 KB/s DVOW with 16 KHz timing

A8B and A6A, are high and the output is low. Lamp

signal DVCLK; and 2) 2KB/s DOW signal. These are all

driver Q9 is turned off and output signal 1CFFL is logic

balanced signals. Output signals are the CVDOW

one. The output of A7B, inverted to high by A6D, turns

signal to module A4 and a status signal to module A2.

on lamp driver Q8 and output signal OCFFL is logic

Change 6 2-16.1