Xref: utzoo misc.wanted:1713 comp.dcom.lans:968
Path: utzoo!utgpu!water!watmath!clyde!rutgers!husc6!linus!philabs!lamont!dale
From: dale@lamont.Columbia.edu (dale chayes)
Newsgroups: misc.wanted,comp.dcom.lans
Subject: Re: PC as RS232 Data Analyzer
Summary: be careful,
	 	you can kill a good (marginal) line by loading it !
Message-ID: <312@lamont.Columbia.edu>
Date: 27 Jan 88 23:47:06 GMT
References: <2473@emory.uucp> <1063@percival.UUCP>
Organization: Lamont-Doherty Geological Observatory N.Y.
Lines: 35

In article <1063@percival.UUCP>, gary@percival.UUCP (Gary Wells) writes:
 in reply to: 
> In article 2600 of misc.wanted Ken Mandelberg asks:
> 
> >In the serial RS232 world, .... special purpose data aalyzers, 

> don't .. need 2 ports..  Most EIA (RS-232) drivers .. handle
> a "bridged" connection, 

Be careful. Adding extra load (another reciever) to a line that is
marginal, may make it worse. There is nothing like finding out (much
later) that your "test" equipment has been running you in circles.

Gary's note suggests that "if you want to get fancy" you could build a buffer.
If you are not really sure, you should do it for safety. An added attraction
of a buffer is that you can add some protection from your computer
inadvertantly sending data.

Another thing to consider when you are probing around in unknown wiring,
is the impact of connecting your pc's serial port directly to nasty things
like power lines. A well designed buffer will help protect you from that 
also.

I thought hard about doing using a "pc" as a serial data analyzer when we
got our first compaq portable here, but concluded that it was too big and
heavy to be a convienient piece of test eqt (we have been using a Tek serial
data analyzer since then.)  HOWEVER, my new Toshiba-1200 is about 1/2 the 
size, and far more powerful, which makes me rethink the problem. For that
matter, any of the new portables would do very nicely.

-- 
Dale Chayes Lamont-Doherty Geological Observatory of Columbia University
usmail: Route 9W, Palisades, N.Y.  10964
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