[RTTY] FSK & 1000MP & MTTY Problem

[NB1B]

I've been trying to key my 1000MP using MTTY and FSK.  I can get it to work
using USB and Rev, but I can't get it to work using LSB and nor.  Any
suggestions that I could try?

LSB and USB phone both work FB.  I just built the FSK Interface, and the
signal sound fine on a second rcvr, but all I get when trying LSB and NOR
are "can't print" replies.

Its got me stumped.  Just made another RTTY QSO, called several times using
LSB and NOR, no reply, then switched to USB and REV and the station came
back in one call.  I think I'm missing something.

Dennis NB1B