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From: len@qumix.UUCP (Leonard Labar)
Newsgroups: net.micro,net.micro.cbm
Subject: Mac interface to commodore printer
Message-ID: <175@qumix.UUCP>
Date: Wed, 7-Nov-84 14:27:11 EST
Article-I.D.: qumix.175
Posted: Wed Nov  7 14:27:11 1984
Date-Received: Thu, 8-Nov-84 08:08:03 EST
Distribution: net
Organization: Qume Corp., San Jose, CA
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Subject: Mac to Commodore printer interface

This is a summary of the request for info on RS422 to IEEE488 that I
posted on the net recently.

1. There was more response than I expected.  The general consensus
seems to be that this requires an extra circuit to handle the timing
but nobody knows what it is.         

2. The Commodore dot matrix printer does not have a standard IEEE488
interface so that is the wrong word to describe it.

3. The timing is tricky.  One response seemed to say that the data is
clocked in on the clock pulses.  Does anyone know the duty cycle of
the clock (on/off time)?  Also, is it clocked by edges or when the
level is low or high.  If I knew this, I might be able to cludge up a
555 timer circuit to generate the clock asyncronously.  Just getting it
to print at all would be a major step forward.