Note: CFS is the same as FSK, TONE is the same as AFSK
Function switch positions are Tone S/R, CFS SEND, CFS REC
Function switch connects the TTY lines to the selected RTTY unit (Tone TU,
CFS Keyer, CFS converter)
(unselected unit lines are shorted by the switch)
SEND terminals are connected only in "CFS SEND" position to
Note - in "Tone S/R" operation, the TU automatically senses the TTY lines and controls the transmitter via PTT
Pushbutton START/STOP momentarily connects to AC SUPPLY to turn on/off
Note: transmitter should latch START line to AC SUPPLY while power is on.
POWER ON lamp is connected between TB102-1 and TB102-4
CARRIER ON lamp is connected between TB102-1 and TB102-4 only when switch is in "CFS SEND" position
TB102 connects to the "Navy standard 6-line transmitter control cable"
Description & Schematic from 1960 ET2 manual
Another schematic from 1963 ET3 manual