Francis,

Good point on the differntial source.  It is a Trimble 332 set down to WAAS only so that the GGA string has the 3 on it rather than 4,5,or,6 for other fixes like RTK, float, and HP or XP which has been an issue with other hardware displays like the AFS a year or so ago that would not take in anything higher than regular DGPS.

We used the harness you describe and you get a comm1 or 2 depending on how you insert into the 26 pin display connector.  Previous firmware version did not let you choose ports and the latest one does.  In both cases it did not work.  What type of receiver did you use and do you have or recall which 9 pin serial pin went to which display pin on the 26 pin connector?

Thanks,

Arnie