Xref: utzoo comp.sys.att:2762 comp.unix.questions:6060
Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!ll-xn!mit-eddie!killer!jfh
From: jfh@killer.UUCP (The Beach Bum)
Newsgroups: comp.sys.att,comp.unix.questions
Subject: Re: parallel printers driving distance on 3B2s
Message-ID: <3683@killer.UUCP>
Date: 14 Mar 88 05:48:27 GMT
References: <57@vsi.UUCP> <1505@nis.NIS.MN.ORG> <356@pvab.UUCP>
Reply-To: jfh@killer.UUCP (The Beach Bum)
Distribution: comp
Organization: Big "D" Home for Wayward Hackers
Lines: 36
Keywords: parallel ports, AT&T 3B2, Centronics

In article <356@pvab.UUCP> robert@pvab.UUCP (Robert Claeson) writes:
>In article <1505@nis.NIS.MN.ORG> pnessutt@nis.NIS.MN.ORG (Robert A. Monio) writes:
>
>>We originally had a 3B2-400 here and had our printer(s) connected in
>>parallel.  The length of the cable was about 12 feet.  We found that
>>if we went beyond 15 feet with our parallel cables that we lost data.
>
>I'm running some printers about 50 feet away over the paralell interface
>of an Encore Annex terminal server. This can be done by using *thick* and
>well-shielded cables. I haven't had *any* loss of data on any of the
>(laser) printers.

this is cheating, i know, but it works quite well.

i have a laser being driven 220 miles on a parallel port.  i convert
the parallel interface into a serial one and feed that into a 4 channel
mux.  the mux in turn is connected to a 9.6KBaud modem where it comes
out the other end of a leased line.  the other end is the same thing in
reverse, finally going into the laser.

cost of the converters was $200 for the pair, plus 64KB memory.  since
the converters can buffer characters while the printer isn't ready,
the line can transmit at close to full speed most of the time.  the
only real slow down comes when raster images are being sent, at which
time the poor mux is swamped ...

well shielded serial lines are _much_ cheaper than parallel ones and
converters are available which run at 38.4KBaud (or higher?).  in
addition, serial can just plain go farther since the timing is less
critical.

- john.
-- 
John F. Haugh II                  SNAIL:  HECI Exploration Co. Inc.
UUCP: ...!ihnp4!killer!jfh                11910 Greenville Ave, Suite 600
"You can't threaten us, we're             Dallas, TX. 75243
  the Oil Company!"                       (214) 231-0993 Ext 260