I found that tweaking the init string is the simplest thing you can do to boost
the k/sec w/ a modem. I'm using a Dualmode Zoom
2919 (56flex/V.90). If I leave the init @ ATZ, my modem works, but is not very
fast, as this is a default setting that works w/ most modems. By changing this
to ATS109=2 (or 1, I forget what I changed it to, V.90 or 56flex only), my
speed is more predictable (usually b/t 45333 and 48000). The server I actually
dial in to could be 30 miles away for all I know. Sometimes, the speed drops
to 26400, so I just hangup and try again. Also, if I use email for a long time
(reading from this list, etc..) I think my ISP drops me, I don't know, I have
to call them cuz in 10 days I've gotten no response from them via email, just
automated replies. Anyhoo...If by any chance you have the documentation that
came w/ your modem, look for init strings specific to that model, or go to
their website.
-Josh
Jeremy Kersenbrock wrote:
> Hello,
>
> I'm having what would seem to be a rather strange problem. My modem almost
> always disconnects suddenly from my ISP after a few minutes online. The
> time varies -- sometimes 20 seconds sometimes 45 minutes. KPPP gives me the
> message "pppd died". Here's the strange part: using the same modem in
> Windows on the same machine calling the same ISP works fine. The modem is a
> USR Sportster 28.8 External.
>
> I do have debug for pppd and kppp enabled, and nothing abnormal shows up in
> the log(s). Linux thinks that the modem simply hangs up and sees no errors.
>
> Also, on the rare occasion when the connection in Linux lasts, the
> throughput is greatly slower than with Windows. I only average 1.3K down
> with Linux and the same setup with Windows get me an average of 2.2K. Then,
> too, I have the registry tweaked up in Windows to adjust the MTU, TTL, RWIN,
> MSS, and NDI Cachesize. BTW, is there any way to adjust these values in
> Linux? I already know how to do the MTU and MRU settings, but what about
> the others. (These two alone seem to make little if any difference).
>
> I've already contacted my ISP (who supports Linux) and he says my problem is
> likely phone line noise (I live out in the country). This is quite
> possible, but then why is Linux so much more picky about it? I have had
> occasional disconnects with Windows, but only a fraction of the number as
> with Linux.
>
> I am using this initialization string with Linux: ATZ. I do not have a
> string specified in Windows.
>
> Is there some remedy for this? Do I need a new modem? or do I give up and
> revert to Windows for my surfing and emailing?
>
> Thanks for any suggesions,
> Jeremy
