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From: jcp@BRL-TGR.ARPA
Newsgroups: net.micro
Subject: Okidata 93 info wanted
Message-ID: <1472@sri-arpa.UUCP>
Date: Sat, 30-Jun-84 15:42:22 EDT
Article-I.D.: sri-arpa.1472
Posted: Sat Jun 30 15:42:22 1984
Date-Received: Sat, 14-Jul-84 13:19:09 EDT
Lines: 29

From:      Joe Pistritto <jcp@BRL-TGR.ARPA>

Folks:
	I just bought the serial/parallel interface converter for the
Okidata 93, installed it correctly, and GUESS WHAT?

	The signal ground line (pin 7), has ~20V of AC on it.  (The board
does pass its diagnostic and the printer is real happy.  Connect it to a
VT-100 though, which connects pin 1 & 7 to chassis ground, and the internal
circuit breaker pops in about 5 seconds though)

	I believe this is due to the fact that they probably split 48V
internally to make -24 and +24 to drive the RS-232.  I suspect its a 'feature',
which means this device needs to be 'isolated' from other RS-232 devices.

	I intend to send the interface back, and buy an external RS-232 to
Centronics interface converter, and am wondering which one to get:

	The two I know about are:

	The Black Box 'Mini Print Spooler' B-PIA90, which is $306
	The Quadram 'Microfazer' 8K QD-MF-SP-8, available from The Bottom Line
		for $149

	Does anyone have experience with these, or have any better suggestions?
(I need to convert the interface to RS-232, but really don't need much buffering,
as I am limited to 1200 baud anyway)

						-JCP-