On Wed, 26 Oct 2005 09:28:40 -0400
"Perry E. Metzger" <perry@piermont.com> wrote:

> 
> "Brad du Plessis" <bradd@cat.co.za> writes:
> > Obviously, a cell phone won't respond to AT commands like a modem, but
> 
> Most do.

exactly. GPRS phones work with an extended version of the AT command set. 

> 
> My EVDO card pretends to be a USB controller with a USB serial device
> attached to it, just so it can pretend to be a modem and take AT
> commands.
> 
> Once we taught the telephants the idea of "Serial + AT commands", they
> never were able to learn anything else. Not enough room for two
> thoughts at once I guess.
> 
> In many cases, though, you have to use "special" phone numbers
> and PPP authenticators to get on line. I suggest using a USB tap
> program to watch the interactions your device has with Windows to
> learn exactly what it does to get onto GPRS.
> 
> Perry

One extra bug-a-boo is that newer nokia phones, e.g. the 6230, have some 
weird CR/LF thing going on that older phones, e.g. the nokia 6200 and 6820, 
don't have. So, the chat script is actually different depending on the age of 
your nokia phone.

For at&t wireless GPRS, my chat script on my 6230 is 

TIMEOUT 10 ''
AT\n OK--AT--OK
ATDT*99#\n CONNECT

for an older phone, remove the "\n". 

Your pppd options file should look something like this:

local
/dev/dtyU0
230400
crtscts
noipdefault
defaultroute
user dummy
noauth
connect "chat -t 20 -v -f /etc/ppp/chat/6230"
ipcp-accept-local
ipcp-accept-remote
noipv6
lcp-echo-interval 0
lcp-echo-failure 0
noaccomp
nobsdcomp
noccp
nodeflate
nopcomp 
nopredictor1 


Several of the above lines probably aren't needed. The ones at the top 
almost certainly are.


-- 
Harry Waddell
Caravan Electronic Publishing
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