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-   -   where to find API for modems (

lavanya.ks 10-04-2007 06:37 AM

where to find API for modems
Hi all, As I am new to embedded linux, i want some tutorial links on "how to write APIs for different types of modems". So please help me by posting the links.

Mara 10-05-2007 04:54 PM

What kind of modem do you mean and what direction (network to device or device to user)?

lavanya.ks 10-06-2007 12:56 AM

communication modems
I want APIs for communication modems such as GSM/GPRS modem, PLCC modem and for PSTN.

Mara 10-06-2007 05:41 PM

So you're going for AT commands (Hayes)? The sets are different from one network type to another, but you an start from the GSM/GPRS ones, which are on the 3gpp site. You may start from 7.07 here: (get the latest version). Note that nearly every vendor adds some extra commands...

lavanya.ks 10-08-2007 01:37 AM

Implimentation of AT commands
I have the AT command set. Actually i wanted to know about how to impliment them in Application program APIs and in kernel to make data transfer.

Mara 10-08-2007 04:28 PM

First, you do not transfer data using AT commands. You only use them to estabilish connection of some kind. Then, using an external application you build an TCP/IP (or other) connection to transfer your data. Can be done using standard tools available in the system (pppd, especially).

If you plan only data transfers you probably don't need any special management of the commands, so they may be simply passed to the port when something requests a connection. If you plan to use a wider set, it becomes more complicated (waiting for one command to finish, breaking commands and so on).

Second thing: it's hard for me to imagine a situation when you need at commands in the kernel. It's application level and that's the way it is usually (99.9%) designed.

lavanya.ks 10-09-2007 12:59 AM

I thought of using AT+CMGS command to send data to other host. Will it work? or any other suggestion on the same?

Mara 10-09-2007 02:58 PM

at+cmgs sends and SMS. If you want to transfer your data this way, you can do it, but only if you plan small transfers. When they're bigger, you need to build partial SMSes on your own.

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