flinton@eagle.wesleyan.edu (11/06/90)
Should there be any reason omitted from my Acermodem 2424 manual explaining
why, in originate mode, my modem should fail to recognize the answer tones
of the modems I dial into more than half the time if ATX4 is in effect,
but connect effortlessly when ATX1 is in effect? (ATM2 is always in effect,
so my ears know it's not any problem with the modem I'm trying to reach.
On the other hand, the failure to recognize _seems_ to be more likely when
the answering modem picks up after only a fractional "ring" signal is heard.)
-- Fred <flinton@eagle.Wesleyan.EDU> or <fejlinton@{attmail|mcimail}.com>tnixon@hayes.uucp (Toby Nixon) (12/03/90)
In article <1990Nov5.193042.35445@eagle.wesleyan.edu>, flinton@eagle.wesleyan.edu writes: > Should there be any reason omitted from my Acermodem 2424 manual explaining > why, in originate mode, my modem should fail to recognize the answer tones > of the modems I dial into more than half the time if ATX4 is in effect, > but connect effortlessly when ATX1 is in effect? (ATM2 is always in effect, > so my ears know it's not any problem with the modem I'm trying to reach. > On the other hand, the failure to recognize _seems_ to be more likely when > the answering modem picks up after only a fractional "ring" signal is heard.) You diagnosis is excellent. This is a well-known problem with modems that are based on certain early releases of the Rockwell V.22bis modem chipset (your modem must be a few years old, right?) These early modems (and on early version of the Hayes Smartmodem 2400 included!), if BUSY signal detection is enabled, MUST see a ringback before they'll recognize carrier. This was because the modem could EITHER look for call progress signals (like RING and BUSY), OR it could look for carrier, but not both at the same time, and if you enabled BUSY detection, the modem wouldn't hear carrier. It was fixed in later versions by switching back and forth between the two modems quickly until something was heard, so current modems, even Rockwell-based, don't have the problem. The way around it is exactly what you've done: use X1. Of course, another way is to set the answering modem to answer on the second ring instead of the first, so at least one complete ringback tone is always heard, but you usually don't have much control over the configuration of the answering modem. -- Toby Nixon, Principal Engineer | Voice +1-404-449-8791 Telex 151243420 Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 P.O. Box 105203 | UUCP uunet!hayes!tnixon AT&T !tnixon Atlanta, Georgia 30348 USA | Internet hayes!tnixon@uunet.uu.net