Page 2
BACK PANEL
The MFJ-1225 provides inputs and outputs to allow interfacing to nearly any possible com-
bination of computer and receiver. The paragraphs below describe their uses. Only a few of the
available connections will be used for any given application; however, the availability of a variety of
signals greatly enhances versatility of the interface.
The first connector is a five pin Kantronics compatible jack. Only two pins are used and they are:
DEMOD
This pin produces a TTL signal which corresponds to the coming RTTY or CW
signal.
GROUND
This pin provides the ground connection between the interface and the com-
puter.
Next is an eight-pin general purpose connector which allows you to adapt the interface to
most any computer and software. From left to right the pins are. as follows:
RTTY INV
This pin produces an inverted TTL level version (a received RTTY signal).
CW INV
This pin provides an inverted TTL level version (a received CW signal).
GND
This pin provides the ground connection between the computer and the in-
terface.
RTTY
This output is a TTL level version of a received RTTY signal.
CW
This output is a TTL level version of a received CW signal. The next pin is not
used.
DEMOD
This pin provides a TTL level signal which corresponds to the incoming CW
or RTTY signal.
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
Cnd of the cable requires an RCA type plug.
SPEAKER OUT
The speaker output jack should be connected to a speaker using shielded
audio cable. The interface end of the cable requires an RCA type plug.
12 VDC
The power jack requires 12 VDC from a 2.5 mm subminiature plug with the
tip positive and the sleeve ground.
