Figure 2-22. Standard clock input inverter switch S1 (viewed from top of input interface card, SM-D-742037, A2AA2A4).

TM 11-5820-803-12

Figure 2-21. 70 MHz input signal range selection switch S1 (viewed from component side of input filter card, SM-D-

7S1133: A2A1A1A22).

direct

support

maintenance

personnel.

If the PSK modem installation requires interface with a

remote digital user over either a shielded cable or a line-

of-sight (LOS) microwave link, the LOS/cable receiver

Figure 2-23. Line driver polarity inverter switches S1 and

and decoder card must be configured to suit the system

S2 (viewed from top of line driver card, SM-D-742053,

requirements. This is accomplished by setting the

A2A2A1A21, A1A2A1A22, A1A2A1A23).

switches on the LOS/cable receiver and decoder card,

shown functionally in figure 2-27, according to the

instructions in paragraph 2-20f. Then the card must be

aligned per the following procedure (refer to figure 2-26

for location of controls and test points):

NOTE

Figure 2-24. External coder interface clock inverter

It is recommended that any spare

switches S1 through S6 (viewed from top of coder

LOS/ cable receiver and decoder

interface card, SM-A-74049, A2A2A2A5).

cards (SM-D742089) provided on the

site also be placed in the modem and

2-21. Circuit Lineup

aliened prior to placing the modem in

NOTE

service.

The following installation procedures

a. The initial adjustments are made at a data rte of

must be made with the assistance of

5.0000 Mb/s regardless of the normal system

2-24