f. Adjusting Transmit Norm/Rev Switch
In most teletypewriter transmission and reception, lower frequency tone is used for mark
pulses and higher frequency tone for space puIses.
Transmit NORM/REV toggle switch
A3A1S1 located on board A3A1 of
transmitter module A3 (see figure)
permits modem to transmit mark-
space tones in reverse, if necessary.
SWITCH A3A1S1 (INSIDE)
Remove module dustcover as described in paragraph 2-9b.
Set NORM/REV switch according to type of transmission required.
Replace module dustcover.
Section III. PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS)
The following information is for QUARTERLY preventive maintenance checks and services (PMCS)
of modem. Quarterly PMCS shouId be performed every 90 calendar days of 8-hour-per-day operation.
Maintenance forms and records to be used and maintained on this equipment are specified in DA PAM
738-750. Perform all checks and services in sequence listed in table 2-1. If the equipment is
operated 16 hours, check at 45 day intervaIs.
PMCS for the modem is limited to exterior and interior of chassis and case
and to exterior of modules ONLY.
a. Tools, Test Equipment and Material Needed for Organizational Level Maintenance
All tools you will need for maintenance on the modem are in Tool Kit, Electronic Equipment
TK 101/G (SC 5180-91-CL-R13).
Required test equipment: Multi meter AN/URM-105 (TM 11-6625-203-12).
Required material: Cement, 3M Co. ED-847