Inbound communication on a modem on GSP

[Jeff_Traigle]

OK. More stupid modem communication problems. We had it working briefly a month or so ago. Spent some time on a system getting it to work again, verifying all of the GSP and inittab settings. Have it to the point that we get the /etc/issue displayed and the login prompt. Unable to type anything, however, so can't login. It's like outbound communication is working to display the stuff, but nothing is going inbound to the system. Replaced the modem cable, think we replaced the modem early in the troubleshooting with this system, but it still strikes me as likely modem/cable issue. Console terminal on the system works. Not sure about telnet access to it since I can't recall if it's connected, but checking with the support person dealing with the customer about that. Any other ideas? (Firmware on the GSP is pretty old, but no older than a lot of other systems that continue to function.)

[Darren Prior]

Hi Jeff,

It sounds like a flow control issue to me. Check the config of the modem itself to see if hardware flow control is expected. Compare this with the output from lssf of the device file that you are specifying in inittab. You then need to align the 2, either both with or both without hardware flow control.

regards,

Darren.

[Dave Unverhau_1]

Jeff, don't discount the modem (again). I've been down the "garden path" with a similar problem where the modem went bad two (or three) times, due to induced lightning or some other freak thing. If the cable works on another system and you're pretty sure your settings are good, I'd see if I could swap that modem to another system known to work (or just hook it to a terminal or PC and dial it from another PC). The failure modes I've seen most often in modems are failure to answer and getting "hard of hearing", both probably due to rogue line impulses.

I hope this is useful...

Best Regards,

Dave

[Jeff_Traigle]

We'd checked flow control. (Was one of the first things I checked and double-checked actually.) The support guys were being slow about getting feedback to me on suggested courses of action. In the meantime, they had another one do the exact same thing, but also had reports that the console terminal was acting flaky too. That kind of led me to believe it was a GSP problem on that one. Don't know. I've moved on to another job now so not my problem to worry about.