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From: plocher@puff.wisc.edu (John Plocher)
Newsgroups: net.dcom
Subject: Re: RS-232 pin 1, line noise
Message-ID: <305@puff.wisc.edu>
Date: Tue, 4-Nov-86 17:33:14 EST
Article-I.D.: puff.305
Posted: Tue Nov  4 17:33:14 1986
Date-Received: Wed, 5-Nov-86 05:19:37 EST
References: <405@vu-vlsi.UUCP>
Reply-To: plocher@puff.WISC.EDU (John Plocher)
Organization: U of Wisconsin CS Dept
Lines: 27

Colin Kelley cries loudly for help with RS-232 interfacing:
>              However, I didn't (and still don't!) know what to do with pin 1
>(Frame Ground, or Protective Ground).

    Frame Ground means just that - GROUND.   Tie this to a real Earth Ground (a
    cold water pipe, the ground pin of the nearest AC outlet...)

>I'm now finding that the longest cable (~50 feet) is having trouble with
>garbage occasionally introduced by noise.

    I'm not suprised - fluoresent lights are REAL BAD in the noise dept...
    do *you*  have any of them near the cable?

>How can I remedy this?  Should FGs of each device been tied together?  Could

     YES

>not doing this have lead to line noise?

      YES

(I was there once, also.  RS-232's a die, then you bitch...)
-- 
"Never trust an idea you get sitting down" - Nietzche
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