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- From: jon_sree@world.std.com (Jon Sreekanth)
- Subject: Re: fax/phone switch
- In-Reply-To: mulvey@blurt.oswego.edu's message of 10 Nov 92 12:34:57 GMT
- Message-ID: <JON_SREE.92Nov11081440@world.std.com>
- Sender: jon_sree@world.std.com (Jon Sreekanth)
- Organization: The World
- References: <oqByTB1w165w@halcyon.com> <22274@drutx.ATT.COM>
- <1992Nov10.123457.788@blurt.oswego.edu>
- Date: Wed, 11 Nov 1992 13:14:40 GMT
- Lines: 25
-
- In article <1992Nov10.123457.788@blurt.oswego.edu> mulvey@blurt.oswego.edu (Allen Mulvey, SUNY, Oswego, NY) writes:
-
-
- When an incoming ring is detected it listens for a CNG tone over the rings.
- If one is detected the call is routed to the FAX. Otherwise it "picks up"
- the line to listen for a modem. The modem must be originating in answer
- mode so it signals immediately upon answering. During this time a pseudo
- ring is sent back, I believe this is so the phone company does not consider
- the call completed in case you never do get through. If a modem is not
- detected, on what would be the fourth ring, the call is passed through to
- the phone (voice) line.
-
- Don't think this is quite accurate. You can't get CNG (or any other
- intelligence, except caller-id) until you go off hook. After going offhook,
- regardless of whether you send fake ringback or not, the phone company
- starts billing. The fake ringback is mostly intended to keep human
- callers or modems happy during the time the fax switch is checking for
- tones. A human caller would be confused by just silence, and a modem
- would miss the ringback cadence and might hangup.
-
- / Jon Sreekanth
-
- Assabet Valley Microsystems, Inc. | Fax and PC products
- 5 Walden St #3, Cambridge, MA 02140 | (617) 876-8019
- jon_sree@world.std.com |
-