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From: dave@dlb.BUCK.COM (Dave Buck)
Newsgroups: comp.dcom.modems
Subject: Re: An interesting modem problem
Message-ID: <191@dlb.BUCK.COM>
Date: Tue, 25-Nov-86 12:33:05 EST
Article-I.D.: dlb.191
Posted: Tue Nov 25 12:33:05 1986
Date-Received: Tue, 25-Nov-86 21:30:18 EST
References: <128@gaia.UUCP> <4070001@hpscda.HP.COM> <18@ucdavis.UUCP> <418@catnip.UUCP> <117@devon.UUCP>
Reply-To: dave@dlb.UUCP (Dave Buck)
Organization: D.L.Buck & Associates, Inc.; San Jose, Calif.
Lines: 31
Summary: Aw, cmon, guys

In article <117@devon.UUCP> paul@devon.UUCP (Paul Sutcliffe Jr.) writes:
>In article <418@catnip.UUCP>, ben@catnip.UUCP (Bennett Broder) writes:
>[ refering to the CTS 2424 modem ]
>> It does have PW (power) and MR (modem ready) which are redundant.
>
>Not necessarily.  MR might indicate the presence (on) or absence (off)
>of DTR.  Most modems won't dial, answer, or do much of anything for 
>that matter, without DTR being high.  Just guessing.

Aw, guys! How about responding if you have some knowledge.
MR is Modem Ready.
Same as Data Set Ready, DSR (back in the olden days,
modems were called Data Sets).
TR is Terminal Ready, same as Data Terminal Ready (DTR).

If you read a bit, you'll find that DSR, or MR (the modem manufacturers have
difficulty with 3-letter acronyms), means the Modem is ready to communicate.
This usually (usually, I said ... depends on manufacturer's alligence to
the specs and on jumper/software switch settings) means the phone has been
answered or a call-out has been made ... on full-duplex modems, it is
usually on when the carrier is up (but not necessarily - there's another
signal, Carrier Detect, which really means there's a carrier).  Now, some
of these new-fangled modems also indicate MR when the modem is ready to
accept commands, and you can also strap it on for peculiar computers or
terminals.

In any case, Paul, presence of power is not the same as modem ready.
And Bennett, you were on the right track, wrong led.
-- 
Dave Buck	(408)972-2825	dave@dlb.BUCK.COM, {amdahl,sun}!dlb.UUCP!dave
D.L.Buck&Assoc.,Inc.	6920 Santa Teresa Blvd.		San Jose, Calif.95119