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MFJ-1225 RTTY/CW COMPUTER INTERFACE
Thank you for purchasing the MFJ-1225 Interface. The MFJ-1225 will allow you to receive
RTTY and CW when used with your receiver and computer. The MFJ-1225 converts the CW or
AFSK tones from your receiver into computer compatible TTL level signals. The computer then
translates these signals into the represented alpha-numeric characters and displays them on the
screen.
NOTE: The interpretation of the TTL signals requires a specialized HAM program which is
not provided with the interface. This allows you to select a program which is compatible with your
computer and which has the features you want.
When unpacking make sure that all of these items are included:
1-interface, 1-five pin plug, 1-eight pin plug, 1-RCA to RCA cable, 1-owner's manual.
NOTE: 12 VDC AC adapter is optional.
FRONT PANEL
The front panel controls and indicators consist of five push button switches and three LEDS. From
left to right, they are as follows:
ON/OFF
This switch controls the power to the interface.
POWER LED
This indicator is lit when the power is on.
PHASE LOCK LED
This indicator is used with DATA indicator to aid in tuning the receiver. It in-
dicates when the interface is locked onto a RTTY signal. It also flashes in
time with the Morse Code tone for CW reception.
DATA LED
This indicator is used with the PHASE LOCK indicator to aid in tuning the re-
ceiver. It flashes on and off with the RTTY shift and also flashes with the
Morse Code tone for CW reception.
RTTY/CW
This switch selects either the RTTY or CW mode of operation.
The next two switches control the shift used for RTTY:
In this position the interface is set for a 850 Hz audio shift
In this position the interface is set for a 170 Hz audio shift
In this position the interface receives with a 425 Hz audio shift.
NORM/REV
This switch inverts the demodulated RTTY signal being sent to the computer.
