Bob Camp wrote:
Hi
The Symmetricom 3805's have an area on the lower board right behind
the "control" DB-25. It's very similar to the 3801. There are three
rows of holes for 0.025" post connectors. One row pair is labeled
RS-232. The other row pair is labeled RS-422. The original intent
appears to be to jumper the unit for what ever standard the customer
desired.
Such was the case on my 3801.. 10 minutes work with a soldering iron and
some wirewrap wire, and it was converted from RS-422 to RS-232.
It's not at all clear that the later units are even stuffed
for the RS-422 option. There are a number of unstuffed IC locations
on the pc board.
Your unit sounds like it's either blown, or running RS-422. I have
never seen one of the earlier HP 3805's so I don't really know how
much they have in common with the older units. There are indeed USB
to RS-422 converters out there that will run on a normal PC.
But unless you're running long wires, or happen to have a RS422
differential system, why bother. If all you're going to do is hook up
the PC to check it out, RS232 is much easier to come by.
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