[TUHS] Compatibility question

Clem Cole clemc at ccc.com
Thu Dec 21 02:22:57 AEST 2023

Until the DECwriter series and the VT04, DEC sold OEM printers and
terminals were made by other manufacturers.   Paul is speaking of the
traditional LP01, which Centronix made (I think) IIRC [Datapoint maybe -- I
forget], and it was ordered with either an upper case only drum [faster -
as it had two copies of the A-Z set] or an upper and lower case drum -
which included some special characters.  The 8-bit parallel interface was
defined by Centronix, which was the standard printer interface for Minis
and later PCs.  The difference with the latter is that IBM used a common
ground wire so they could put it in a DB25S connector. With the PC, IBM
designed the interface using a bi-directional Intel parallel I/O chip so
you could read it - which was not true of the earlier interfaces for

As for the LP01 drum, it was possible to replace in the field but a PITA
[we did when we got a used one from Tektronix's Finance shop that was
running RSTS Cobol and moved it to the Teklab's 11/70 - V7++ UNIX system].

FWIW: when the Printronix was released in the late 1970s, it became the
standard lineprinter for UNIX sites until the rise of laser printers.

As for putting a 1403 on a PDP-10, I suspect it was possible, but it
probably took some custom interfacing.

On Wed, Dec 20, 2023 at 11:08 AM Adam Thornton <athornton at gmail.com> wrote:

> On Tue, Dec 19, 2023 at 11:14 PM Mary Ann Horton <mah at mhorton.net> wrote:
>> I vaguely recall, as a teen, taking a tour of a DEC-10 shop in about 1970
>> in Portland. Their printer played "Anchors Aweigh" and I never knew how.
>> But now I wonder - does this mean they had an IBM 1403 connected to a DEC
>> 10 somehow?
> It certainly means they had some kind of chain or train printer, but any
> place big enough to have a PDP-10 would probably have had the budget for a
> serious printer as well.  I don't know if DEC made a competing printer (I
> think they were very early with dot matrix printing?) or not (or who other
> than IBM made big lineprinters),  but once you know the trick is possible,
> the rest is a relatively simple matter of having someone with a good ear to
> tune the printer output so it sounds right.
> For a modern and delightful analogue to this, have a look at the
> Floppotron.  https://www.youtube.com/@PaweZadrozniak
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