[GreenKeys] M33 questions

[gil smith]

Hi folks:

First, a couple of questions on standard 33s:

The M33-asr with the auto-reader option, has the fourth "AUTO" position on
the reader switch.  I don't have my manuals handy, but I kinda remember the
xon/xoff codes being used to start/stop the auto-reader, when in the AUTO
position.  So was there a function lever that turned a relay on and off to
power the reader or something?  Where was the relay?  Can a non-auto reader
be modified to work this way?  Was the little box in the stand the power
supply for the reader?  This simply turned the reader on and off for
streaming operation, did it not?

Also, to provide a delay after CR, to allow the carriage to fully return,
it seems that X number of nulls were usually sent -- what would X be?

And now for some DEC-specific questions:

In considering hooking up a 33 to a pdp-8 clone I built, I have run into
some tape issues that are not clear.

Apparently DEC had their own interface for M33 machines.  The main
connection was a 20-mil loop, using half-duplex I think.  There may have
been full-duplex applications using two loops, I don't know. 

For paper tape reading, DEC systems provided a signal for a "reader run
relay" apparently for stepping the tape reader one char at a time, not just
streaming on/off.  Some have said this was another 20-mil loop, while
others have said it was a 12VDC signal.  Does anyone have any info to share
on these DEC-interfaced machines?  Did they use a special reader, the
auto-tape-reader, or just a standard reader?  Can a standard asr be
modified to work this way?  Did they just use private-wire CCUs with
DEC-specific interface stuff in the stand, or did they have a special CCU?
Do my questions ever end?

thanks,

gil
  





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