The R-392 receiver has three multi-pin connectors on the front panel. Two are for audio and the third is for power and connection to the companion T-195 transmitter.
The following charts describe the signals on each connector pin.
The two AUDIO connectors are wired identically--the corresponding pins on each are wired in parallel to allow either or both to be used with loudspeaker, headset, and/or microphone.
Pin Signal Description
A AF output 600 ohm audio output , same as pin L and J103 pin H.
B Ground
C Microphone This signal is not used by the receiver, passed to transmitter via J103 pin C.
D No connection
E Ground
F Push to talk This signal is not used by the receiver, passed to transmitter via J103 pin F.
H Ground
J No connection
K Carrier relay This signal is also available at J103 pin K
Grounded by the receiver when the audio output is not squelched.
L AF output 600 ohm output from the receiver, same as pin A and J103 pin H.
The J103 connector is used to provide power to the R-392 receiver and to provide control of the optional companion T-195 transmitter.
Pin Signal Description
A 28 VDC B+ Tube plates power, requires 0.5 A.
B Relay Contol This signal is provided by the transmitter to engage relays in the receiver to disable the audio output and antenna input when transmitting. This signal is ignored when the receiver Function switch is in the NET position to allow simultaneous use of the transmitter and receiver.
C Microphone Provided to the transmitter from pin C on the AUDIO connectors.
D 28 VDC Tube filaments power, requires 2.5 A.
E Ground
F PTT switch Passed to the transmitter from pin F on the AUDIO connectors.
H AF output 600 ohm audio output, common with pins A and L on the AUDIO connectors.
J No connection
K Carrier relay Also pin K on the AUDIO connector and is grounded by the receiver when the audio output is not squelched.
When operating the R-392 receiver not connected to a T-195 transmitter supply power the receiver as follows.
+28 V at 3 A J103 pins A and D in parallel
DC Ground J103 pin E
It is possible to split the DC plate and filament supplies. Some users report better sensitivity by running the plates at more than 28 volts. The filament supply should remain at 28 volts.