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- Newsgroups: comp.dcom.modems
- Path: sparky!uunet!newsstand.cit.cornell.edu!pelican.cit.cornell.edu!rdc
- From: rdc@pelican.cit.cornell.edu (Bob Cowles)
- Subject: AT recognition problems
- Summary: Modem doesn't recognize AT if line speed above 9600
- Message-ID: <1992Aug21.044856.24963@pelican.cit.cornell.edu>
- Date: Fri, 21 Aug 1992 04:48:56 GMT
- Organization: Cornell Info. Tech.
- Keywords: AT 19200
- Lines: 28
-
- I have tried two different Zoom Vfx modems and several different
- serial cables on a PS/2-80 and I cannot get consistent recognition
- of the at command at serial port speeds above 9600. The modems
- seem to work fine at the other end (an RS/6000 running AIX 3.1.6)
- in terms of responding to an at command regardless of the speed.
- I have tried running both DOS and OS/2 on the machine with the same
- result. Running a hardware information program on the machine turns
- up the result that it has an 16450 UART.
-
- I was unable to run any of the other Fax software that came with the
- modem (Winfax 2.0 and METZ), so I purchased FaxIt (aka PMFax). When
- PMFax failed I was able to turn on it's tracing mode and discovered
- that even whenI told the config that the port was 9600, PMFax would
- initialize at 2400 and then switch to 19200 for the dialing and
- transmission ... since the modem only recognizes about 50% of the
- at commands at that speed, the probability of getting a complete
- transmission at that speed is really remote. In data mode, if I can
- get it to understand the atdtnnnnnnn command, then I'm OK ... but that
- often requires entering the command several times. One other bit of
- information is that if the at command is recognized, the "sd" light
- will flicker when I press enter at then end of the command, if the
- command is not recognized then no light, no response, nothing.
-
- Any suggestions would be greatly appreaciated.
-
- Bob Cowles
- rdc1@cornell.edu
-
-