W076/M452 replacement cards

From: vrs <vrs_at_msn.com>
Date: Thu Nov 27 09:49:31 2003

> Some place in the pdp-8E/M docs there must be specs for the TTY and
> reader control circuits. Take a look at the TTY I/O prints and see
> what devices DEC used to drive the relay circuit.

The circuit used in e/m machines appears to be overkill -- it can drive
100ma, and kinda had me worried. I rechecked the circuit used in the 8L,
and it looks set up for about 30ma. I can do that without too much trouble.
If I can't find a TTY to test with, I'll just spec the resister value for
30ma and hope it works out :-).

    Vince
Received on Thu Nov 27 2003 - 09:49:31 GMT