Figure 6-42.--Link panel test set.

operating the appropriate lever switches and the

Test Equipment

selector switch, various system conditions are

Preventive maintenance must be performed on the

simulated. The module response is indicated by the

MDM system to keep it in good operating condition

various test lamps located on the panel. The switches

and lamps are connected so that the three modules

and to prevent interruptions in service. When

tested use many common test set components. The test

corrective maintenance is required, special test

set requires an external source of ring voltage and dc

equipment is needed to complete the work. In the

power. These normally can be obtained from terminals

following paragraphs the major special test equipment

located at the switchboard.

for the MDM system will be discussed.

The description of controls and indicators listed in

COMMON PANEL TEST SET.-- The common

table 6-7 corresponds to the common panel test set in

panel test set (fig. 6-41) is used to test the common

control, link allotter, and level detector circuit

modules of the MDM 50- and 100-line units out of the

LINK PANEL TEST SET.-- The link panel test

system. The purpose and function of the 50/100-line

set (fig. 6-42) is similar to the common panel test set.

system and the 200/700-line system are the same.

It is also used on the 50/100-line system. The one used

There are some physical characteristics that are

for the 200/700-line system functions in the same way

different. The module to be tested is plugged into the

but has some physical differences. It is used to bench

test the link circuit modules. To test the module, the

jack receptacle located on the face of the test set. By

Figure 6-42.--Link panel test set.

6-45