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- Newsgroups: comp.sys.ibm.pc.hardware
- Path: sparky!uunet!gatech!usenet.INS.CWRU.Edu!agate!linus!linus.mitre.org!jcmorris
- From: jcmorris@mwunix.mitre.org (Joe Morris)
- Subject: Re: Dial tone, but no dialing
- Message-ID: <jcmorris.715443177@mwunix>
- Sender: news@linus.mitre.org (News Service)
- Nntp-Posting-Host: mwunix.mitre.org
- Organization: The MITRE Corporation
- References: <24355@oasys.dt.navy.mil> <24407@oasys.dt.navy.mil> <92245.133640FWR100@psuvm.psu.edu>
- Distribution: na
- Date: Wed, 2 Sep 1992 14:12:57 GMT
- Lines: 34
-
- FWR100@psuvm.psu.edu writes:
-
- >In article <24407@oasys.dt.navy.mil>, dowling@oasys.dt.navy.mil (John Dowling)
- >says:
- >>
- >> I have a perplexing problem (at least to me it is) and I was hoping
- >> somebody out there has run into a similar problem and solved it. I
- >> have a Compudyne 2400 baud fax/modem (internal) installed in an AT machine
- >> I built myself. Recently, I've run into this problem; when I go to
- >> dial out, I can hear a dial tone for about 5 or 6 seconds, but no familiar
- >> touch-tone dialing. After 5 or 6 seconds, the dial tone is lost and
- >> the message "NO DIALTONE" comes up.
-
- >Before dialing, your modem listens for a dialtone. The exact sound of the
- >dialtone depends on your local telco exchange and is not always what the modem
- >expects to hear. You need to tell your modem to "dial blindly" without waiting
- >for a dialtone. You can check your manual, but ATX0 usually works.
-
- Another possible problem would be that your telephone wires are crossed.
- Many modems monitor the telephone connection by watching the polarity of
- the battery on the telephone line and will not recognize the presence of
- dial tone if the wires are crossed.
-
- It doesn't help that some telephone extension cords are pinned to invert
- the line and some are pinned to maintain it.
-
- Incidentally, some pushbutton telephones are unable to generate the DTMF
- (TouchTone (r)) signals if the line polarity is wrong.
-
- Try reversing the red and green wires (those are the only ones that matter
- for most uses) somewhere between your modem and the telco line and see
- if that fixes the problem.
-
- Joe Morris / MITRE
-