PDP 11/05 - looking for help - looking for Jorg Hoppe?

Dave Wade dave.g4ugm at gmail.com
Mon Feb 12 06:43:35 CST 2018

> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of sop00000h
> via cctalk
> Sent: 12 February 2018 11:22
> To: cctech at classiccmp.org
> Subject: PDP 11/05 - looking for help - looking for Jorg Hoppe?
> Jorg Hoppe:
> I am the proud owner of an old pdp11/05.  I does not have a M9970 (nor can
> find one).  So I cant do 20ma/rs232 output.  I read in somebodies note
> jumpers @W1 and W2 on the M7261F that I have.  Apparently cutting one of
> these disables the onboard uart and will allow me to put in a serial card.
> cant find the jumpers.  Nor can I find a print set.  Any suggestions?

Its not a slim line 11/505 is it, in which case you don't appear to need the
If its not would it be possible to make an M9970. They appear to be just


Or pick up the signals from the wire wrap as described here :-


you can pick-up the signals fron the backplane, with a wire-wrap
send data+ 20ma-tty FE2
sent data- 20ma-tty FJ2
sent data ttl-level DF1
Gnd on DC2 and DT1
rec data+ 20ma-tty FN1 
rec data- 20ma-tty FP1
rec data ttl-level FM1
Gnd on FC2 and FT1

Hope this helps. Just what I found by googling as I was curious as to what
an M9970 was


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