Cingular will let you sign up for service and just give you a SIM 
card. They also have some recommended modules, primarily from Nokia. 
You pay a flat fee per month that comes with a minimum amount of time 
or you can pay so much per minute similar to a regular call.

You have the option of doing as you say by calling a modem or they 
have information on how to send your data packaged in SMS messages 
which are relayed by them to your computer over the Internet.

I spoke with the Sparkfun people mentioned elsewhere and they claim a 
SIM card from Cingular will work in one of their Telit modules.

Our project did not go forward because of the cost. Even quoting 
several thousand numbers Cingular's price was not low enough and none 
of the other US companies had good coverage in the areas we needed. 
Instead we used Zigbee modules to link from our equipment to an inside 
location where we piggybacked off existing telephone circuits.

Tim


Harold Hallikainen wrote:
> I have an application where an embedded cellphone module would be useful.
> I'd like something that does low speed serial data (14.4kbps or so) over a
> national (US) cellular network. Data would be exchanged infrequently (once
> a week to once a month). Does anyone know of such a module and what sort
> of arrangements can be made with cellular companies to do such data
> exchanges at off peak times, ideally only paying for data exchanged
> instead of a "per unit" cost?

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