MFJ-1224 Instruction Manual
RTTY/CW Computer Interface
5
AUDIO IN The audio input jack should be connected to the external speaker jack or
headphone jack of your receiver with a shielded audio cable. The interface end of the
cable requires a RCA type plug.
SPEAKER OUT The speaker output jack may be connected to a speaker using shielded
audio cable. The interface end of the cable requires a RCA type plug.
12VDC The power jack requires 12VDC from a 2.5mm sub miniature plug with the tip
positive and the sleeve ground.
PRELIMINARY CONNECTIONS
Input and output signals must be TTL level (+5VDC and ground). Inputs are RTTY and
CW KEY(RTTY and CW on general purpose connector). There is also a separate CW ID
input for identifying in MORSE while operating RTTY. Outputs are DEMOD (RTTY
DEMOD and CW DEMOD on the GINERAL PURPOSE CONNECTOR) and DIRECT
and GRID BLOCK. Connections depend on the type of computer and transceiver used.
Either the GENERAL CONNECTOR or the K-CONNECTOR will be connected to the
computer.
CONNECTIONS
FOR CW
For transmission and reception of CW, the following connections are
necessary.
1.) A 12VDC power supply to the POWER jack of the interface.
2.) A shielded audio cable from the external speaker jack of the transceiver to the
AUDIO IN jack of the interface.
3.) If desired, a speaker may be connected to the SPEAKER OUT jack of interface.
4.) If the interface is to be used to key the transmitter by hand, the key should be
connected to the KEY IN jack.
5.) The control cable from the computer to the interface.
6.) A cable from one of the KEY OUT jacks of the interface to the KEY IN jack of
the transceiver. If you are not sure whether your transceiver requires GRID
BLOCK or DIRECT KEYING, try one and then the other to see which one works.
No damage will be done if the wrong one is selected.
