HP2748A papertape reader : connector ?

From: Bob Shannon <bshannon_at_tiac.net>
Date: Sun Jul 1 10:00:10 2001

Jay West wrote:

> Bob Shannon wrote...
> > > This is incorrect!
> > >
> > > The HP tape reader uses a HP tape reader board that is unique, it is NOT
> the HP
> > > 8 bit duplex register board.
>
> Bob is incorrect for the 2100 as well as the entire 21MX M/E/F (and HP1000)
> lines. He could very well be right on the 2114/5/6 cpu's though.

"Incorrect" may have been a poor choice of words....however I have documentation

that shows a HP2100 shipped by HP with the older reader interface board. In
fact
one of the reader boards I have was removed from a basket-case 2100 system.

I wounder when HP switched over, and why?

> The HP 2748B paper tape readers were connected to an HP2100 or HP21MX M/E/F
> system via the 8-bit duplex register board. No other interface was used, at
> least for sale in HP configurations. Matter of fact, if you bought the paper
> tape reader kit (the part # escapes my mind) which included the paper tape
> reader, the HOST interface board, cables, manuals, and diagnostic, there was
> only one interface you would ever get. The 8-bit duplex register. This was
> the HP designated interface for the 2748B.

The documentation I have for the tape reader kit shows the older, reader
specific board
rather than the duplex reg. Hmmmm, what gives here?

> I can only assume Bob is referring to the older 2114 (not actually an HP
> machine other than the label), 2115, and 2116 machines which I'm not as
> familiar with. I have however, seen 2748B paper tape readers hooked up to a
> 2116 with an 8 bit duplex register so I know that to say in general terms
> that the HP tape reader board is unique and not the 8 bit duplex register
> board isn't accurate. But I can't speak from experience on the 2114 or 2115.
> Of course, the 2114/5/6 are NOT 2100 machines, and of course they're not
> 21MX M/E/F systems either. So, perhaps early 2114/5/6's had a modified paper
> tape reader and a unique interface at that time, but certainly not after the
> 2116.
>
> Jay West

Umm, how is the 2114 not an HP machine? (The 2114 was developed by HP.)

Your thinking of the 2116 perhaps, which was originally developed by a small
firm that
HP later absorbed?

Also the 2116 was HP's first computer, not the 2114. The 2100 came after the
2114, and
at least 1 2100A shipped using the older style interface board. My 2115 also
came with
the old-stype tape reader board, and that clearly came after the 2116.

(the first computer HP actually designed was the 2115, simply a re-packaged
2116)

My guess would be that HP decided to use the duplex board, and stop production
of the
reader-specific board to simplify their inventory. This means that some of the
HP tape
reader cables out there are wired for the original tape reader interface board,
while others
are wired for the duplex register. Using the wrong cable could cause problems.

>From what info I have, it appears that the switch from the original Tape Reader
I/F to
the generic duplex register must have happened in or after 1970 or 1971.

What is your definition of a '2100 machine'?

2114, 2115, and 2116 machines run HP 2100 software, and were the original
processors
used in HP2000 time share basic systems. They originated the HP board interface
used
all the way up to the MX and E series. The software on the HP2100 archive site
is that
which originally shipped with 2114 thru 2116 systems.

If these classic machines are not 2100's, then what are they?
Received on Sun Jul 01 2001 - 10:00:10 BST