How to use both a VT-52 and an ASR-33 on a PDP-8A

dwight dkelvey at
Mon Feb 22 13:18:47 CST 2016

You could use something like an Arduino to buffer
either. It could take the 9600 from the terminal and
retransmit it at 110. It would be slow when updating
data to the terminal but it should be able to buffer human
input at the terminal.
That way, all of the current loop would be at 110 baud.
The terminal could then be either current loop or RS232.
It doesn't sound like too complicated a job.

From: cctech <cctech-bounces at> on behalf of Marc Howard <cramcram at>
Sent: Thursday, February 18, 2016 7:40 PM
To: General Discussion: On-Topic Posts Only
Subject: How to use both a VT-52 and an ASR-33 on a PDP-8A


Just looking for suggestions on how best to setup my PDP-8A so that it can
use either a VT-52 (current loop version) or an ASR-33.

One idea I have is a multi-pole switch to change the baud rate from 110 to
9600 and to also switch the xmit and rcv current loops.

Does anyone out there have any other suggestions?



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