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AT Commands

02 Apr 2014
AT commands are used for communicating with a modem. AT is the abbreviation of ATtention commands. Every command start with AT. Some of the useful AT commands are listed below. You can call a number, attend a call, hang a call, send sms, read sms, and the list goes on with the features of a particular provider. Some commands are specific to some models. GSM modems can be bought and can be integrated to Micro-controllers or directly to PC. Following list may be helpful to hobbyist or others working on GSM modems for project works.

AT
The response will be OK. This means that the modem is up and ready.

ATD94xxxxxxxx
This command will initiate a voice call to the no 94xxxxxxxx. The semicolon indicates that it is a voice call. If you want to run any USSD codes like *123# for balance enquirey, do the same without semicolon.

ATD*123#

Other Call control commands
Command
Description
ATA
Answer command
ATD
Dial command
ATH
Hang up call

 

Sending an SMS.


First put the modem into text mode. Otherwise output will be in hex format.

AT+CMGF=1

Then

AT+CMGS="+94xxxxxxxx" > This is the text message
Then press Cntrl+z to complete typing message and send it. You will get a response like

+CMGS: 100 OK

 

Reading a message

AT+CMGR=<indexofmessage>

For example

AT+CMGR=1

The response will be the message indexed at 1.

Some other AT commands :
Command
Description
AT+CBC
Battery charge
AT+CSQ
Signal quality

For a whole set of AT commands refer this link..
Link
For a quick overview of some useful commands go to this site.
Link.

For how to communicate (like sending message, calling etc) using a microcontroller and a GSM modem (like SIM300) am gonna write a post soon.

How to hide and unhide files in Linux?

31 Mar 2014

If you are new to linux OS, it’s a common mistake to add a (.) in front of your files and suddenly the file disappears. In Linux filenames starting with a dot (.) are hidden. You can intentionally make a folder or file hidden by renaming it.mv filename .filename If you want to view you hidden files or folders, first go to the location where the file resides using cd command.

Linux: How to find your serial (any connected) device?

31 Mar 2014

In Linux all devices that are connected to the system are listed in/dev If you connect your mouse to your system it will detect it as hidraw. Other serial devices will be named as tty0, tty1,etc. So if you connect a serial (any) device and you want to know it’s name ( for ex: you want to connect it via minicom ), first go to /dev using

Serial Port Communication in Linux using Minicom

30 Mar 2014

First of all install minicom using

www.ieeegecskp.in

29 Oct 2013

After a weeks hard work www.ieeegecskp.in is now up and running.This site was designed for the IEEE Student Branch wing of my college (Govt. Eng College Sreekrishnapuram).