[time-nuts] z3801a - serial help and for sale.

Bob Camp kb8tq at n1k.org
Wed Jun 10 17:27:36 EDT 2015


Normal drill for this sort of thing:

1) First connect the serial dongle back to back (output to input) and make sure 
it gives you back what you type in. If not, find another dongle.

2) Check the output levels from the Z3801 with a scope. It should be swinging at least
+/- 5V and more like +/-12. The key thing here is that the swing is the same in both directions.

Then, in combination, try each of the following:

3) Try the usual suspects in terms of parity: 8N1, 7E1, 7O1

4) Try the usual speeds: 4800, 9600, 19200

A quick power cycle between each of the 9 possibilities should get it feeding 
out something that you can recognize. Yes this is a generic approach, but sometimes
the generic one is quicker than doing a bunch of research, looking for notes on how you
switched the thing around back months ago ….


> On Jun 10, 2015, at 10:28 AM, David Andersen <dga at pobox.com> wrote:
> I'm throwing my hands up in the air - I don't have the time to wrestle my
> silly mac into trying to talk to the box, unless someone has quick advice
> on something I might be doing wrong.
> z3801a, jumpered to RS232, modified with an internal switching power supply
> (see photos below).  Power light comes on, unit is outputting stable
> 10MHz.  Doesn't GPS lock, but that makes sense, since I haven't been able
> to issue a SURVEY command and I don't live where I used to.
> The internal green status light is blinking (as normal), suggesting that
> it's probably happy and I'm an idiot for not being able to make it work,
> but I don't vouch for anything about it past the 10mhz being there.  The
> double-oven oscillator is clearly happy given the 10mhz (compared against a
> working Thunderbolt).
> Hooked up a serial cable at 19200, 7, O, 1, but only got a garbled little
> prompt back - no response to standard z3801a commands.  I *think* I have
> the cable configured properly.  I opened it up and checked the RS232
> jumpers and they're correct.
> I'm open to advice on getting the serial working under my Mac or Linux, or
> anyone who wants to relieve me of the burden of z3801a ownership and take a
> risk that it's a fixer-upper. :-)  I suspect that in some previous life, I
> switched it over into a binary mode of some sort while using it to sync
> something, but I can't for the life of me remember what I might have done.
> Some reasonable price plus shipping and it's all yours... I'm trying to
> de-clutter in preparation for a sabbatical on the other side of the country.
> Pictures:
> https://www.dropbox.com/s/ursszjgie8m1xj8/2015-06-09%2011.57.16.jpg?dl=0
> https://www.dropbox.com/s/it8d2f65ztn4rkq/2015-06-09%2011.57.24.jpg?dl=0
> https://www.dropbox.com/s/1p1g6xrapzdmvzh/2015-06-09%2011.59.56.jpg?dl=0
> Thanks!
>  -Dave
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