Modem keeps disconnecting

I have been trying to get my plug n play card to work correctly with linux for a while now.  I can can actually dial my ISP or some BBS board successfully.  The problem is that I cannot stay connected for no longer than a couple of minutes before I am disconnected, and returned an error 'No Carrier'.  If I am quick enough to get a file to download, I will stay connected until the file is completely downloaded, then I'm disconnected.  I assumed then that the CPU provides the plug n play card with some continuous signal to ensure online connection via Win95, which I also have
installed on my system.  I then went and bought a cheap 33.6 modem card to test this assumption.  The result, actually turned out to be the same.  That is when I am disconnected, I recieved the error 'No Carrier'.  This isn't a real easy problem to solve, and would expect a detailed answer that would explain what the problem is; how it can be solved; and if it can't be solved what are the alternatives.  Also is there a way that I could "fake" the modem into thinking that it has a signal in order to stay connected.  I am thinking to do this, I probably would need to write a device driver, something I would like to not do if possible.

As for checking noise on the telephone line, it is about as clean as it is going to get.  I also disable call waiting when I dial out, so call waiting is not the cause either.  Also, I cannot find any interrupt conflicts that may be causing this problem, so I suspect that this isn't the problem either.

I need all the help that I can get on this matter to solve this problem.
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

shipleyAuthor Commented:
Edited text of question
use a kernel compiler with the serial driver intergrated (not in a module)


Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Some questions:

a) What chipset is your modem?
b) What chipset does your ISP use for their modems?

Call your telco and ask them to do a silence test. If you're in the UK get a NETCOM account and do their modem-info test to give you a graph of attenuation.

Try writing S10=254 to the modem as part of the init.

If it's a PnPray problem, you could try running isapnptools (search Altavista for that). But if a "cheap modem" gives the same result then you're looking at a line problem. Move all your modem cables away from power sources. Disconnect any other telephony devices on the line.  

Run irqtune to increase the IRQ priority (this made a lot of differnce for me a while ago with RH 3.3.3).

Finally, after all that, get an engineer from the telco to check your line.
shipleyAuthor Commented:
I tried adding S10=254 to init string, but the modem reported an error.  As for irqtune, I cannot locate it on my linux system.  My modem is a 336F by Best Data (Smart One Series).  What else can I try to get my modem working properly.
You could try forcing a V.FC connect - +MS=74 off the top of my head - check out the manual. If this holds the line, then you're looking at line noise in the high range which upsets V34.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Linux Networking

From novice to tech pro — start learning today.