Path: utzoo!utgpu!water!watmath!clyde!rutgers!husc6!hao!oddjob!gargoyle!ihnp4!cbosgd!osu-cis!tut!mdf
From: mdf@tut.cis.ohio-state.edu (Mark D. Freeman)
Newsgroups: sci.electronics
Subject: How to connect grounds when using RJ11 for RS232
Message-ID: <6561@tut.cis.ohio-state.edu>
Date: 14 Feb 88 06:03:50 GMT
Organization: StrongPoint Systems, Inc.; Columbus, OH. (guest of Ohio State U.)
Lines: 28


Yes, I know how stupid this question is.

We are starting to use multiport boards in our multi-user microcomputer
systems.  The boards have 8 6-wire modular phone-type jacks on them.
We are running cable through the walls which has 2 twisted pairs and a
shield.

At the terminal end, we attach a male RJ11 to the wire coming from the
comuter, and plug it into the terminal through an RJ11->DB25 adapter.

Most of the time, we only need Send Data and Receive Data connected, as
we are using XON/XOFF handshaking.  The rest of the time, we need to
add Clear-to-send.  So that takes care of two or three wires.
RS232 provides for a pin 1 ground and a pin 7 ground.  The cable's
shield ought to be connected to something, but all the connectors are
plastic.

The question, what do I connect the cable's shield to?  If I can only
connect one ground, which should I hook up?  If I can hook up both,
should I bother?


-- 
Mark D. Freeman						  (614) 262-1418
					      mdf@tut.cis.ohio-state.edu
2440 Medary Avenue	   ...!cbosgd!osu-cis!tut.cis.ohio-state.edu!mdf
Columbus, OH  43202-3014      Guest account at The Ohio State University