Lesson 1/Learning Event 2
The TA-236/FT is a general purpose common battery telephone (manual or dial). Range of
operation is approximately 5 miles from central office location. Outgoing signaling is dial pulse and
incoming signaling is 90V AC, 20 Hz. Power requirements must be provided by a central office or
common battery switchboard. The handset consist of the receiver and transmitter compartments and is
connected to the base plate assembly by a four-conductor handset cord. The base plate assembly serves
as a mounting plate for the network ringer, ringer volume control, dial, and hookswitch contacts. The
housing assembly is the black plastic case which covers the base plate assembly. A three-conductor
deskstand cord connects the set to the telephone circuit with use of a connecting block as a tie point. On
the schematic diagram, the circuit components are shown with schematic symbols representing the
actual component. For example, the network is a sealed unit, but on the schematic it is shown by the
schematic symbols for coils, capacitors, varistors, and resistors which make up the network.
The repairer must be able to identify the various components of the TA-236/FT and orientate the
schematic symbols and diagram to the components represented before he can successfully begin to
troubleshoot and repair the telephone set.
Learning Event 2:
The repairer must know the various circuits that comprise the TA-236/FT. The circuits of the
TA-236/FT are ringer, transmitter, receiver, and antisidetone circuits.
The theory of operation for the TA-236/FT circuits is described in the TM 11-468 Extracts. The
student will be able to trace and explain these circuits.