Note. (Added) The basic manual covers Manual Telephone Switchboard SB-249/TTC, serial numbers 1 through 321, and Trunk Relay Telephone Circuit TA-226/TTC, serial numbers 1 through 107. Manual Telephone Switchboard SB-249/TTC, serial numbers 322 through 780, is similar to the switchboard described in the basic manual except for circuit modifications that permit dialing without the use of a special dial cord and that also permit ringing on the answer cords. Trunk Relay Telephone Circuit TA-226/TTC, serial numbers 108 through 260, is similar to the trunk relay case described in the basic manual except for circuit modifications that permit dialing without the use of a special dial cord.
DesignationTM 11-2146
EditionOct 1954
StatusSuperseded
Pages240
FunctionComms Signal
CollectionHistoric
Public domain (U.S. Government work)