A transistorized 20-channel carrier telegraph terminal

摘要

Since its introduction in 1938 the FM (frequency-modulated) carrier has found ever-increasing use in the Western Union Telegraph Company. The gradual evolution from the type-15 to the current type-40 carrier telegraph terminal has shown an increase from two telegraph channels per bay, to 10 channels in the same space. The equipment herein described mounts two 10-channel groups per bay along with associated power supplies, bias and leg controls, and metering and monitoring facilities. This design has been designated as the type-60 channel terminal.