tnixon@hayes.uucp (Toby Nixon) (10/18/90)
In article <3401@idunno.Princeton.EDU>, vnend@phoenix.Princeton.EDU (D. W. James) writes: > Princeton has a bank of 4 Telebit T2500's to service its UUCP > connections. A few of those are 2400 baud no-name modems that > seem to be happy connecting to just about any other 2400 baud > modem, but that die when they try to connect to the Telebits. > ... > protocals, then finally starts sending a 2400 carrier. At that > point my modem starts to handshake, then hangs up abruptly. It's possible that the modems on the host side have their S7 registers set to a lower-than-normal value, providing only a limited time to establish a connection before hanging up. It's also conceivable that the host itself allows only a certain amount of time between detecting an incoming call (RING) and DCD going high, or it drops DTR and gives up. In either case, it's necessary to take action on the host side to alleviate the problem. Have you tried forcing your T2500 to V.22bis/2400-only mode and connecting? Does it work? -- Toby Toby Nixon, Principal Engineer | Voice: +1-404-449-8791 AT&T: !tnixon Hayes Microcomputer Products Inc.| Fax: +1-404-447-0178 CIS: 70271,404 P.O. Box 105203 | UUCP: uunet!hayes!tnixon MCI: 267-0805 Atlanta, Georgia 30348 USA | Internet: hayes!tnixon@uunet.uu.net
jmc@teqsoft.UUCP (Jack Cloninger) (10/18/90)
vnend@phoenix.Princeton.EDU (D. W. James) writes: >Princeton has a bank of 4 Telebit T2500's to service its UUCP >connections. A few of those are 2400 baud no-name modems that >seem to be happy connecting to just about any other 2400 baud >modem, but that die when they try to connect to the Telebits. Did you try setting S-register 92 = 1 in the T2500? The proper command is: ATS92=1&W This is the "Answering Sequence Selection" register. Setting it to '1' will cause the PEP tones to be sent out last. Some of the low speed modems are disturbed by PEP tones. We use this config- uration and it works fine. It does not disturb PEP to PEP connections, since the Telebits are not disturbed by the other modem tones. I hope this helps. Jack -- Jack Cloninger, TeqSoft, 112 US Highway 1, Tequesta, FL 33469 B-) ...uunet!comtst!teqsoft!jmc Phone: 407-747-7163 Fax: 407-747-0354
kam@dlogics.COM (Kevin Mitchell) (10/18/90)
In article <3401@idunno.Princeton.EDU>, vnend@phoenix.Princeton.EDU (D. W. James) writes: > What happens is that my (for example) modem calls in, the Telebit > goes through its attempts to connect using PEP and some other > protocals, then finally starts sending a 2400 carrier. At that > point my modem starts to handshake, then hangs up abruptly. We > watched the telebits today: the carrier detect light comes on on > them, but by that time my modem has disconnected. The CD light on > my machine never comes on, but the recieve data light flashes. Try telling your modem to wait longer for carrier. Also, setting voice detection (X6 on USR modems) causes the modem to hang up immediately when it hears the high speed protocol stuff. -- Kevin A. Mitchell (312) 266-4485 Datalogics, Inc Internet: kam@dlogics.UUCP 441 W. Huron UUCP: ..!uunet!dlogics!kam Chicago, IL 60610 FAX: (312) 266-4473