13 Oct
2003
13 Oct
'03
6:22 a.m.
Date: Sat, 11 Oct 2003 09:04:11 -0400
From: Ian Primus <ian_primus(a)yahoo.com>
Subject: Re: ASR33 Teletype interfacing
>> I have been attempting to get my ASR33
teletype connected to something
>> and communicating, but so far I have not been successful. I have built
Teletypes are
inductive loads. Though they only want 20 mils, the
voltage needs to be high to get the initial magnet pull-in (basic RL
theory). ASR33 loops were generally run at 100V or so, but I run my
Model 28 at 14V, with non-perfect error rate, and I don't use the
keyboard.
I take it that the voltage isn't that crucial, just the current? The keyboard
and printer are IN SERIES. If you hit keys while it's
printing you foul it up. Normal.
What about on a full duplex machine? Is it the same, or are they
separate? I've done
one of these fairly recently, and if poked with a
not-too-sharp stick, I'll scan the schematic and pu on my website.
*poke*
<grin>
If it's not too much trouble, I'd like to see it. From what I have
heard, there are lots of ways to do this, and i would be very
interested to see how you did it.