Re: Forcing modem connection to 57600 bps
Its likely that windows is actually reporting the speed to the UART chip
on the modem and not the actual connect speed (i've it do this to me
before) which would be 57600 for a 56k modem. Trying to force your modem
to a higher speed is probably not a good idea. I see you are .fi so the
US FCC limit to 53kbps shouldnt apply to you, and i dont know how valid my
next statements will be, but analog lines are generally noisy, and your
modem talks with the remote side to negotiate the fastest speed the can
talk to eachother over the lines and still understand eachother. By
forcing your modem to go faster, you need to get the remote side to go
faster as well, and likely your line cant handle a faster speed without
corruption to the bitstream, so in eaiter case you are likely to get bad
data if you force the connection to go faster. I've seen lines so bad 56k
modems connect a 26k, and the highest ive seen is 50k, and that was only
once.
-Casey
On Tue, 16 Jan 2001, Jarkko Niemi wrote:
> After using my dial-up connecton with speed reporting I wanted to force
> my modem up to it's maximum speed. It works from windows side, so, it's
> just up to configuring it also to Linux. Windows doesn't help, there is
> just one box where to check as "[] use always this speed", no AT
> commands found there (was that really a suprise?).
>
> By the way it's internal ISA modem named
> SupraExpress 56i SP Intl
>
> So, I went to look modem's AT manual and edited /etc/chatscripts/
> I added AT+MS= part just before number dialing.
> I don't know do I use wrong AT command, or are parameters wrong,
> anyway it calls, but not connect.
> By commenting that out, everything works like earlier - giving usually
> 48000 or 46667 connects.
>
> Any ideas where to look next?
>
> /etc/chatscript/<script> is here
> # This chatfile was generated by pppconfig 2.0.5.
> # Please do not delete any of the comments. Pppconfig needs them.
> #
> # ispauth pap
> # abortstring
> ABORT BUSY ABORT 'NO CARRIER' ABORT VOICE ABORT 'NO DIALTONE' ABORT 'NO DIAL TONE' ABORT 'NO ANSWER'
> REPORT CONNECT
> # modeminit
> '' ATZ
> # reports connection speed (jin)
> OK ATW2
> # forcing modem speed to maximum (jin)
> OK AT+MS=,0,56000,56000,,,
> # ispnumber
> OK-AT-OK ATDT<my-isp>
> # ispconnect
> CONNECT \d\c
> # prelogin
> # ispname
> # isppassword
> # postlogin
> '' \d\c
> # end of pppconfig stuff
>
> /var/log/ppp.log looks like that
> Jan 16 13:50:00 jin pppd[360]: pppd 2.4.0 started by root, uid 0
> Jan 16 13:50:01 jin chat[364]: abort on (BUSY)
> Jan 16 13:50:01 jin chat[364]: abort on (NO CARRIER)
> Jan 16 13:50:01 jin chat[364]: abort on (VOICE)
> Jan 16 13:50:01 jin chat[364]: abort on (NO DIALTONE)
> Jan 16 13:50:01 jin chat[364]: abort on (NO DIAL TONE)
> Jan 16 13:50:01 jin chat[364]: abort on (NO ANSWER)
> Jan 16 13:50:01 jin chat[364]: report (CONNECT)
> Jan 16 13:50:01 jin chat[364]: send (ATZ^M)
> Jan 16 13:50:01 jin chat[364]: expect (OK)
> Jan 16 13:50:01 jin chat[364]: ATZ^M^M
> Jan 16 13:50:01 jin chat[364]: OK
> Jan 16 13:50:01 jin chat[364]: -- got it
> Jan 16 13:50:01 jin chat[364]: send (ATW2^M)
> Jan 16 13:50:02 jin chat[364]: expect (OK)
> Jan 16 13:50:02 jin chat[364]: ^M
> Jan 16 13:50:02 jin chat[364]: ATW2^M^M
> Jan 16 13:50:02 jin chat[364]: OK
> Jan 16 13:50:02 jin chat[364]: -- got it
> Jan 16 13:50:02 jin chat[364]: send (AT+MS=,0,56000,56000,,,^M)
> Jan 16 13:50:02 jin chat[364]: expect (OK)
> Jan 16 13:50:02 jin chat[364]: ^M
> Jan 16 13:50:02 jin chat[364]: AT+MS=,0,56000,56000,,,^M^M
> Jan 16 13:50:02 jin chat[364]: OK
> Jan 16 13:50:02 jin chat[364]: -- got it
> Jan 16 13:50:02 jin chat[364]: send (ATDT<my-isp>^M)
> Jan 16 13:50:02 jin chat[364]: expect (CONNECT)
> Jan 16 13:50:02 jin chat[364]: ^M
> Jan 16 13:50:47 jin chat[364]: alarm
> Jan 16 13:50:47 jin chat[364]: Failed
> Jan 16 13:50:47 jin pppd[360]: Connect script failed
> Jan 16 13:50:48 jin pppd[360]: Exit.
>
> --
> Jarkko Niemi Oh Dear! Said Pooh-bear, and deleted Windows
> jin@sci.fi ----====( finger jin@sci.fi or http://www.sci.fi/~jin )====----
>
>
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