Telemetry, where to start?

[Donald]

Does anyone have any recommendation cellular CDMA/GSM modem that can be
embedded and that will work in the US? It seems finding a cellular
modem in the US is more difficult than what I thought it would be.

Maybe I am not sure what to look for. I found some modems but they are
huge and I am not sure if they work directly with a microcontroller.

Also, the remark from Donald that it will not work in the US worries me
and I am not sure I understand why. I know cars have telemetry that is
wireless, how do they do it?

Thank you all for your replies.

A

My discussion with cell phone people (years ago) led me to believe that
security was at issue.

I beleive Marc, in that the US cell phone companies are interested in
charging more for data services.

The units sold at sparkfun.com web site state:

"You will need to provide a SIM card. Pull the SIM card from your phone,
insert it into the module, and viola, you are making calls under your
cellular account. Works with all providers currently supporting SIM
cards (AT&T, T-Mobile, and Cingular)."

So, the bottom line here is that no-one in the US sells cheap
off-the-shelf cell phones with a simple serial interface ( like
everywhere else in the world).

Donald

PS: the cars have a modules like the GM862 Cellular Module.

 

[Chris Hills]

Don't know about the US, but the best site for this stuff is TDC's:

http://www.tdc.co.uk/gsm/gsm_siemens.htm

Unfortunately as the US entered the market late they developed their own
standard so the "European" (global) system did not walk straight in to
the US. It was a form of protectionism.

In the early days you could use your sim in the US but had to change
phones. Now most phones are tri or quad band however not all services
are availible.

Ironically the when the US "liberated" Iraq they decided to bring the
Iraqi mobile phone system up to date by installing the US system. That
had to be canned when the Iraqi's realised it was incompatible with the
GSM system used by everyone else in the middle east

There are also some advantages, in the current security situation, why
the GSM system is preferable. It is also probably the same reason why
the data services in the US are not the same as Europe.

 

[Chris Hills]

My discussion with cell phone people (years ago) led me to believe that
security was at issue.

There is a security issue. The problem is the US is paranoid. Though to
be fair most of the world is out to get them these days,

I beleive Marc, in that the US cell phone companies are interested in
charging more for data services.
The units sold at sparkfun.com web site state:

"You will need to provide a SIM card. Pull the SIM card from your phone,
insert it into the module, and viola, you are making calls under your
cellular account. Works with all providers currently supporting SIM
cards (AT&T, T-Mobile, and Cingular)."

So, the bottom line here is that no-one in the US sells cheap
off-the-shelf cell phones with a simple serial interface ( like
everywhere else in the world).

Looks like a market opportunity. OTOH it is possible that there is
"request" from the US government not to make those services easily
available.