[time-nuts] Newbie With a Z3801 Problem

Mark Sims holrum at hotmail.com
Fri Nov 4 22:37:42 EDT 2016

I recently got in a KS24361 system to test Lady Heather with.  I was having a terrible time talking to it.  Lady Heather would detect it (at 19200,7,O,1 on the GPS box, 9600,8,N,1 on the non-gps box).  Nothing I did would get it to accept commands.  Turns out that the GPS box speaks SCPI at 19200,8,N,1 and my detection routine sent a <CR><LF>  at 19200,7,O,1 and looked for the SCPI> prompt.   The unit accepted the <CR><LF> and responded (Heather does not care about pairty on reponses) so I assumed the serial port parameters were properly configured,  but any real commands sent would not be recognized.

Once that was sorted out, the other problem was getting the GPS receiver initialized.  I could not get it to accept a position.  Also it would not automatically re-survey (after a week it had not done a survey).   That problem was that I was connected to the non-GPS box and thought it would send the commands over to the GPS box.  It was responding as if it had accepted the commands, but nope, GPS related commands are only actually processed when connected to the GPS box.

Lady Heather now has a terminal emulator built in... makes it easier to to diagnose serial port issues and play with sending various SCPI commands.  Another issue that I had was I tried using a null-modem 25-9 pin cable on a Z3801A.   NULL MODEM was molded into the cable connectors.  No go.  It was wired a straight through cable... grrrr... wasted a lot of time on that one.

Until you can talk to the Z3801A with a terminal program and verified your connection and serial port parameters,  forget about using SATSTAT and GPSCON, etc.  Even Lady Heather's auto-detect routine can get fooled by improper parity settings.

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