[comp.os.vms] DMF32 -> Centronics interface

JEREMYM@EPVAX.SUSSEX.AC.UK.UUCP (11/26/87)

We have connected up our HP Laserjet series II to the printer port of a DMF32,
but it is necessary to make up a simple circuit to invert the strobe and
busy lines, which can be powered from the printer.

You should also ensure that the DMF32 is correctly configured to
support an LP32 by setting switch 4 of switch pack 3 OFF. (this is located
on the distribution panel).

The connections are as below:

    VAX     signal      HP

    26      DATA1        2
    30      RET         20
    20      DATA2        3
    24      RET         21
    22      DATA3        4
    28      RET         22
     1      DATA4        5
    33      RET         23
    24      DATA5        6
    25      RET         24
    23      DATA6        7
    34      RET         25
     5      DATA7        8
    30      RET         26
     6      DATA8        9
    28      RET         27

          |\
     8  --| \O----       1      Inverter on STROBE
          | /
          |/

    14     CONN VFY    GND
    12     ON LINE      32    FAULT

            /|
    18  --O/ |----      11      Inverter between DEMAND and BUSY
           \ |
            \|



We use pin 18 on the HP to provide 5v for the 74LS04 ic, decoupled by 100uF

NB the DMF32 manual is WRONG. The strobe is on pin 8 NOT 37 !!!

We set up the printer thus:

$ set printer/cr/lowercase/printall/passall lca0:

and define appropriate forms for our prestige font cartridge ( I'll mail them
if anyone wants. They're pretty trivial, though.)

To print graphics, do a $print/passall to stop the  print symbiont messing
around.

DISCLAIMER: If you blow anything up, dont't blame me! It works for us.
---------------------------------------------------------------------------
Jeremy Maris
Experimental Psychology,     |  JANET:  jeremym@uk.ac.sussex.epvax
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