HP2748A papertape reader : connector ?

From: Jay West <west_at_tseinc.com>
Date: Sat Jun 30 02:44:35 2001

The 2748A/B paper tape reader uses the "8-bit duplex register interface".
That would lead me to believe it's an 8 bit interface, not a 16 bit one.

I have full docs (& schematics I believe) for both the 2748B and the 8-bit
duplex register interface board. I have two of those units presently
running, so I can get the cable pinout too if you'd like (but I believe the
cable diagram is in the interface manual). Let me know if you still need

One word of caution about the facit 4070 punch... as I found out when I got
mine - the facit had a board in it that was replaced depending on what
electrical spec the system you were attaching it to used. I seem to recall
that you had to specify which (of many) interfaces you wanted on the punch
when you ordered it. So just because you find a 4070 punch doesn't mean it
has the right board in it to hook up to the 8-bit duplex register board (hp
punches and readers both used the 8-bit duplex register board). Matter of
fact, unless it was found with an HP system, it probably DOESN'T have the
right board for the HP. You can't tell from the outside either, as I've seen
the RS-232 interface board in the punch presents a DB25 externally - just
the same as the HP version of the card does (which is decidedly NOT RS-232).

Jay West

----- Original Message -----
From: Tony Duell <ard_at_p850ug1.demon.co.uk>
To: <classiccmp_at_classiccmp.org>
Sent: Friday, June 29, 2001 12:41 PM
Subject: Re: HP2748A papertape reader : connector ?

> >
> > At 09:22 PM 6/28/01 +0200, you wrote:
> >
> > >A recent dumpster dive yielded a HP2748A papertape reader. Does anyone
> > >the interface spec's for this device handy ?
> >
> >
> > I think *some* of HP's paper tape punches and readers use the
> > parallel interface. It's a 16 bit parallel interface with several
> I suspect this is highly likely since the 16 bit parallel interfaces,
> like the 82032, 98032 (for the 9825, etc) were used for many
> (and other) peripherals.
> > additional handshaking lines. Each data line can be set as Input only,
> I would be suprised if a paper tape reader used all the capabilities of
> that interface, though. Most likely there are 8 outputs from the tape
> reader (1 per data track), a data strobe signal (produced from the
> sprocket track, and either an input signal to cause the reader to advance
> one character (and read it) or one to start the tape moving, whereupon
> you get data strobes every so many ms. Maybe signals for error (tape run
> out, etc) and direction control
> There's not that much you need for a paper tape reader after all...
> > Output only or In and Out. I think have one around here somewhere that
> > off of a PT punch. You should have grabbed the PT punch, I think the
> > is what HP used or perhaps I should say one of the ones that they
> The Facit 4070 is what _everyone_ used :-). Yes, HP used it for a time
> (one of the options for the 98032 is certainly to connect to a 4070, and
> it was used with larger machines as well). So did Philips (on the P800
> series). I've got a 3rd party card to link it to the DEC Unibus, and
> information on a similar card for Omnibus. Oh, and my Fluke DVM system
> has an option card to drive the 4070.
> I've even seen other paper tape punches (Trend made one based on the GNT
> Model 34 mechanism) that have the same interface. The 4070 was almost a
> de facto standard for paper tape punches.
> > used. What kind of connector is on your PT reader? I think most of
> If its's the unit I'm thinking of, it's a connector similar to the ones
> used for V.35 interfaces.
> -tony
Received on Sat Jun 30 2001 - 02:44:35 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:34:01 BST