MFJ-1224 Instruction Manual
RTTY/CW Computer Interface
4
Next is a eight pin general purpose connector which allows you to adapt the interface to
almost any computer and software. An internal DIP switch allows the inputs and outputs
to be inverted if necessary to correspond to the requirements of your computer. From left
to right, the pins are as follows:
RTTY DEMOD This output is a TTL version of a received RTTY signal.
GROUND This pin provides the ground connection between the interface and the
computer.
CW ID This input pin controls the shift for CW ID transmission.
RTTY This input pin controls the mark and space shift for RTTY transmission.
PTT This input controls the push-to-talk switch of the transmitter.
CW KEY This input controls the transmitter keying circuit.
+5VDC This input provides a 5 volt supply for external circuitry such as an RS-232
converter.
Next is a five-pin jack which is used for the microphone connection. From left to right,
the pins are as follows:
PTT OUT This pin is connected to the high side if the push-to-talk line. It is shorted to
ground to key the microphone.
PTT GROUND This pin is connected to the ground side of the push-to -talk line.
AFSK SHIELD This pin is connected to the ground for shield side of the AFSK line
AFSK OUT This line carries the audio signal for AFSK RTTY to the microphone input.
FSK OUT This line provides FSK signal for keying FSK rigs.
