I remember at least one contact with this sort of cabling arrangement. The
v.35 normally uses a distinctive rectangular connector while most
manufacturers like the cheaper 'D' connectors. The use of the 'D'
connector has more to do with cable-assembly cost than anything else, and
it may not be assumed that there is any implication of signal
compatibility.
If you intend to play with the v.35, you may want to look at the standard
before risking the health of your interface hardware. I haven't looked at
it in years, but IIRC, it's a differential arrangement at ECL levels or
something on that order. I say this because I seem to have seen ECL logic
used to generate the levels in at least one piece of equipment. I don't
much regret that I don't remember the details. Now that amateur ISP's are
running high-speed telecom interfaces, e.g. DS-3, from their basements,
we'll undoubtedly see this one more often.
Dick
----------
From: Bruce Lane <kyrrin(a)bluefeathertech.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Subject: Re: V35-RS232 cable?
Date: Friday, February 26, 1999 7:28 AM
At 20:33 25-02-1999 -0500, you wrote:
>Hello, all:
>
> One of my recent acquisitions is a Roytron paper tape punch/reader.
>Before I actually got it, it had a v.35-to-DB25 cable on it . Now it
>doesn't, of course.
>
> I'm ignorant (about many things, but particularly) about v.35, so
could
this have been
an RS-232 adapter cable? If so, how could I make one?
It's not just a simple cable in a case like that. There would also be
some
level-shifting electronics involved for at least the
data leads because
V.35 is a differential interface.
I'm a little surprised to hear of a V.35 cable on something like a paper
tape handler. Are you sure the thing really does have a V.35 interface,
and
that Roytron didn't just happen to use the same
connector that V.35
devices
do?
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Bruce Lane, Owner and head honcho, Blue Feather Technologies
http://www.bluefeathertech.com
Amateur Radio:(WD6EOS) E-mail: kyrrin(a)bluefeathertech.com
SysOp: The Dragon's Cave (Fido 1:343/272, 253-639-9905)
"Our science can only describe an object, event, or living thing in our
own
human terms. It cannot, in any way, define any of
them..."