[GreenKeys] ASR33 punch reader control line

[Christian Gauger-Cosgrove]

Hello!

Sounds like you have a DEC LT33 modified teletype, or similar. Put +12 on
the extra plus 12 and -12 on the control line. I think it to needs 20mA to
activate the reader run relay.  Based on the document I am looking at right
now.

Though, if it isn't a DEC LT33 (their nomenclature for a 33ASR with a
reader run relay), it could be different.

Cheers,
Christian Gauger-Cosgrove




On Sunday, 5 May 2013, Trammell Hudson <hudson at osresearch.net> wrote:
> I'm attempting to connect an ASR33 with a current loop interface to a
modern computer and am not sure how to connect the punch reader control
lines.  In Local mode the punch reads fine and prints a copy of the tape as
you can see in this video:
http://www.flickr.com/photos/osr/8662034542/in/set-72157633270866016
>
> In Line mode, however, the tape reader does not do anything.  I believe
the control line need to be pulsed to clock in one byte, but have not been
able to find documentation on the interface specifications.  There are two
remaining wires in the cable and the label says they are "+12v reader" and
"Ctrl-line".  So I assume it is not yet another current loop, but sending
various voltages on the control line (shorted to ground, to my interface's
+5, to the +12v, etc) did not seem to have any affect.
>
> Thanks!
>
> --
> Trammell
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