rajkumr@arnor.UUCP (Ragunathan Rajkumar) (03/28/91)
We have a NetBlazer acting as a Slip/Telnet gateway using T2500 modems.
Currently, a maximum of 4 people call in. In the lab, things work just fine.
Two callers have NO problems with SLIP or telnet. Two others, including
me :-(,
have all kinds of problems: either CD never comes on, or if it does, junk
characters show up and the connection never materializes. "Failed
synchronization" is the modem's diagnostic. On rare occasions, things work as
they should but they are so rare, we have given up on these two phone lines.
I have tried all kinds of modem settings to get around this problem but the
situation is as non-deterministic as it can be: drives me crazy! My suspicion
is that I am experiencing basic telephone line problems: most likely at the
local exchange or between the home and the exchange ("last mile"?). The calls
are local (about 10-15 miles separate the caller and the callee modems) but are
in reasonably congested areas (I get the message "Your call did not go through!
Try your call again later" rather regularly).
Have others experienced this? Is there a way to test/confirm my
suspicions? Is
there a known solution? Should I blame Telebit, the local exchange, or just my
stars? ANY help would be MUCH appreciated.
---
Raj
Ragunathan (Raj) Rajkumar rajkumr@watson.ibm.com (914) 784-7931gandrews@netcom.COM (Greg Andrews) (03/29/91)
In article <1991Mar28.001515.102@arnor.uucp> rajkumr@ibm.com writes: >We have a NetBlazer acting as a Slip/Telnet gateway using T2500 modems. > >[some folks] have all kinds of problems: either CD never comes on, or >if it does, junk characters show up and the connection never materializes. Gee, sounds like the callers aren't able to make the initial connection, and/or a speed mismatch shows up when they do. Where is the speed mismatch happening? On the caller's end? What modems are dialing in? > "Failed synchronization" is the modem's diagnostic. That's not a result code the modem could issue. Where are you getting this report? >On rare occasions, things work as they should but they are so rare, we >have given up on these two phone lines. > >I have tried all kinds of modem settings to get around this problem but >the situation is as non-deterministic as it can be: drives me crazy! >My suspicion is that I am experiencing basic telephone line problems: >most likely at the local exchange or between the home and the exchange >("last mile"?). The calls are local (about 10-15 miles separate the >caller and the callee modems) but are in reasonably congested areas >(I get the message "Your call did not go through! Try your call again >later" rather regularly). > >Have others experienced this? Is there a way to test/confirm my >suspicions? Is there a known solution? Should I blame Telebit, the >local exchange, or just my stars? ANY help would be MUCH appreciated. > At this point, I'm not sure anybody deserves your 'blame'. How about applying some basic testing principles to the situation: 1) Let's find out if the modems can connect together. Try putting one of the T2500s back to factory defaults and hooking it to one of the phone lines. Disconnect the modem from the NetBlazer. Dial into the modem and see if the modems can connect and stay connected. Enable MNP in the answering T2500 and try some more. Disable MNP and enable V.42 in the answering T2500 and try that also. If the originating modem supports PEP, try that type of connection and check the reports generated by the S71 and S73 registers during the connection. Be sure to call from just a dumb terminal or a computer that's emulating a dumb terminal. DON'T call from a unix system with a chat script - you want to K.I.S.S. while you're performing tests. 2) If the above work okay, hook the T2500 up to the NetBlazer and dial into it. Stay with a dumb terminal on the calling end (only change one thing at a time). See if you can log into the NetBlazer and do normal telnet-type stuff. We're just trying to get connected and stay connected without any fancy footwork. 3) If the above both work, then try automated calls into the T2500 and NetBlazer. Don't start doing SLIP yet. Just do normal interactive login stuff like #2 above. 4) Now you can try automated stuff and SLIP. Somewhere along the way from step 1 to here, you'll have run into the problem and will know what's causing it because you know what part of the link you started using. In short, start with the modem-to-modem connection and work your way outward to the computers and software. Telebit Modem support and NetBlazer support aren't giving you any suggestions about this kind of thing??? -- .------------------------------------------------------------------------. | Greg Andrews | UUCP: {apple,amdahl,claris}!netcom!gandrews | | | Internet: gandrews@netcom.COM | `------------------------------------------------------------------------'