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From: tnixon@hsfmsh.UUCP (Toby Nixon)
Newsgroups: comp.dcom.modems
Subject: Re: Picking phone up while modem in use
Message-ID: <3619@hsfmsh.UUCP>
Date: 21 Jul 90 03:42:43 GMT
Sender: daemon@hsfmsh.UUCP
Organization: Hayes Microcomputer Products, Inc.  Norcross, Georgia
Lines: 59

In article <5851@jhunix.HCF.JHU.EDU>, Lan S Hsieh writes:

- Shouldn't Hayes compatible modems hang up the phone that's plugged
- into them so picking up the receiver while the modem is in use won't
- interrupt the comm link? 
- 
- Our modem doesn't do that and it is a major problem because we have
- several phones in the labs (plugged INTO the modem, not before) and
- we get disconnected when someone picks up the phone in another room.
-
- I talked to the Viva techie and he claims that even real Hayes
- modems don't disconnect the line coming out of them. 

The techie is wrong.  Real Hayes modems DO disconnect the PHONE jack 
from the line whenever the modem is off-hook, precisely for the 
reason you describe: to prevent you from inadvertently interrupting 
your call by picking up that phone.  Of course, the modem can't 
affect other phones on the same line, but only those that are 
connected via the PHONE jack on the back of the modem.

Many modems made by other manufacturers do not do this.  It takes an 
additional relay, adding some expense and board space.  This is only 
one of the many little reasons why Hayes modems cost a little more, 
but, as you can see, those little things are sometimes important.

Whether or not you have some kind of "claim" against these folks is 
doubtful.  "Hayes compatible" is not any kind of a legal term; it is 
very subjective, defined by the company using it, not by Hayes.  It 
generally refers to the fact that the modem implements some portion 
of the Hayes AT Command Set (although nobody but Hayes implements 
ALL of it).  Your question was whether or not "Hayes compatible" 
modems "should" cut off the phone attached to the PHONE jack; the 
answer is, "That's a design decision the manufacturer makes."  If 
you require that feature, you need to ask whether or not the modem 
has it before buying the modem.

You might be able to get around this cheaply, however.  Radio Shack 
and many office supply stores carry devices called "Answering 
Machine Stoppers".  Normally, you plug it into the wall jack, then 
plug your answering machine into it.  Then, if your answering 
machine picks up on the line to quick for you, you can still take 
the call -- from any phone in the house -- by just picking up.  The 
"Stopper" detects that another phone is off-hook, and cuts off the 
answering machine.  I'm sure you could rig it so that all of the 
other phones were plugged into the "cutoff" side of the stopper and 
the modem was plugged into the other jack, so that whenever the 
modem is off-hook that the phones are cut off.  These devices 
generally cost from $5 to $10.

	-- Toby

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Toby Nixon, Principal Engineer     Fax:    +1-404-441-1213  Telex: 6502670805
Hayes Microcomputer Products Inc.  Voice:  +1-404-449-8791  CIS:    70271,404
Norcross, Georgia, USA             BBS:    +1-404-446-6336  MCI:       TNIXON
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