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TNC Radio Port Pinouts

Step 1: Modulator Alignment

Step 2: Demodulator Alignment

Step 3: Tuning Indicator Alignment

This website is devoted to "Care and Maintenance of the MFJ 1278B TNC"--I use one of these for RTTY and PACTOR, and for years (well, six) I have run AFSK using the tones output from the round circular plug in the back--the RADIO1 jack.  These tones were fed into the back of a Kenwood TS-450S which was set on the LSB mode, thus producing RTTY, AMTOR, and PACTOR.

I have learned that the MFJ 1278B is unstable, and I'm sure that if you have ever used one, you have become frustrated at its' performance...sometimes it just seems like you are not even transmitting a signal.  But guess what? The real problem is that the 1278 is out of whack and the receiving station is getting nothing but garbage....

If you can, definitely run a line from the TTL output header in the back of the 1278 to the RTTY terminal in the back of the radio.  If not, then you will be forced to run AFSK and will need to periodically check the output of the 1278 to make sure the tones are still on frequency. 

I also have some real gems here for the 1278 look around and come back often!!

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Serial Cable Pinouts

RFI Symptoms & Cures

Pactor ID Command

Soundcard Modes on the 1278??

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