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From: jhc@mtune.ATT.COM.UUCP
Newsgroups: mod.telecom
Subject: Re: Using RJ-11 connectors for RS-232 lines.
Message-ID: <8702042312.AA13353@mtune.ATT.COM>
Date: Wed, 4-Feb-87 23:12:24 EST
Article-I.D.: mtune.8702042312.AA13353
Posted: Wed Feb  4 23:12:24 1987
Date-Received: Tue, 10-Feb-87 06:28:30 EST
References: <8702020437.AA03157@starfish.Convergent.COM>
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: mtune!jhc@harvard.HARVARD.EDU (Jonathan Clark)
Organization: AT&T ISL Middletown NJ USA
Lines: 26
Approved: telecom@xx.lcs.mit.edu

>In article <8702010550.AA07252@ucbvax.Berkeley.EDU>, rdsnyder@MIT-CCC.UUCP writes:
> The person proposed to use modular telephone connectors for connecting
> RS-232 serial lines.  and that is how they should be used lest some bozo
> should happen to plug an RS-232 cable into a telephone jack

It is for this exact reason that AT&T's Premises Distribution System
utilises a resistor-capacitor pair, inside the little module which
also converts from a 4-pair modular jack to a DB-25. They call this
beast a 'Terminal Protector'! That way if a terminal gets plugged in to
an analog line which is ringing, the cheap little module gets fried and
not the expensive terminal. Mind you, the terminal protectors aren't
exactly cheap...

Modular connectors do have significant advantages over conventional
RS-232 DB-25 connectors, especially the brain-damaged ones on the IBM
PC and clones.
-- 
Jonathan Clark
[NAC,attmail]!mtune!jhc

My walk has become rather more silly lately.
---
Jonathan Clark
[NAC,attmail]!mtune!jhc

My walk has become rather more silly lately.