Help needed: AS33 understanding Reader Run Control

From: Gerold Pauler <gerold.pauler_at_gmx.net>
Date: Tue Feb 3 21:04:44 2004

Hi,

in the process of restoring one of my teletypes I decided
to connect it to a PC. Send and receive work fine, but the
tape reader does NOT work in line mode (local is no problem).

It is an ASR33 relabeled by HP and has a HP Reader Run Control Card.
I have put a schematic of this card online
http://pdp8.de/download/HPtty.pdf
(Couldn't figure out the types of T1 and D1 - so these can be a pnp or
a zener diode also. Polarities of reader run signals (RDR+/RDR-) can
also be wrong.)

But I am too dump to understand how to connect the reader run signals.
I'm not even sure what levels they should have.
I just thought that a circuit identical to TX (on PC side aka RX on
teletype) should do.

If you need additional infos to help please let me know.

TIA
        Gerold (pdp8.de)
Received on Tue Feb 03 2004 - 21:04:44 GMT

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