[time-nuts] Z3816A rs-232 interface

Robert Melville bobmelville1 at gmail.com
Fri May 11 02:39:22 EDT 2018

I am getting some very peculiar behavior with the serial interface on
my GPS rcvr (Z3816A).

I have tried several computers and several different GPS utilities
(GPS-DOS2, Sat Stat, GpsCon, etc.).

To date, the only thing that works is Sat Stat on a windows 2000 computer.
I am using a Null modem and set the monitor computer to 9600-8N1.

Other computers and/or utilities seem to give irregular behavior.

I have looked at the signals with a scope and they seem borderline OK.
The signals (Rx and Tx) swing a bit more than +/- 7 V. There is also some
digital noise riding on the lines.

I also notice that the -15 Vdc line on the internal power supply is not
(it reads about + 1.2 V).
Someone on the web I found a posting claiming that the -15 Vdc line is not
for the Z3816A.

Any help would be appreciated.
1. Is 9600-8N1 correct?
2. Could the lack of the -15 Vdc line be the root cause?
3. Has anyone managed to use GpsCon with a Z3816A?

Thanks much for any input!

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