[time-nuts] HP Z3801A Communications

Charles Watkins idcity84 at atcnet.net
Mon May 19 00:15:10 EDT 2008

Hi Dick, I've been silently enjoying all the comments that Time-Nuts Digest
has had to offer for some time now, and have been too timid to respond (or
simply not smart enough).  I do have a solution if you do not want to make
the RS232 conversion on the Z3801A.  Originally I made a 422 to 232
converter using a free sample chip from Maxim.  I believe it was the MAX232.
It worked fine, and I still have it.  I mounted all the required surface
mount components "dead bug" style on a small piece of perf board and mounted
that within a DB-25 back shell.  The only drawback with the circuit was that
I had to provide an external 5 volt supply and since I did not want to
intrude into the PC, I used an external bench power supply.  I eventually
bit the bullet, and made the modification inside the 3801.  Glad I did, it's
much simpler now and unless you need the long line length that RS-422 can
handle, the 232 mod is well worth it.  If you want further info on the
MAX232 method, I can take pictures of the one I built and dig up the
schematic I used.  However, it can be found on the web, I just can't locate
the links right this minute.

Good luck,

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