WEEK 3 - 3rd Day ( 11 July 2012 )

Assalamualaikum and Salam satu Malaysia.

From my last task in previous day, Mr Mazran told us understand  about AT command in GSM Modem. So today me, Syuhada and also Fauzan  have given GSM Modem to us to try it out.The tasks are sending SMS and receive SMS. 

GSM modem is specialized type of modem that operates over subscription based wireless networks which is similar to a mobile phone. A GSM modem accepts a SIM card, and basically acts like a mobile phone for the computer. Traditional modem is attached to computers for ‘dial-up’ to connect with other computer systems. A GSM modem operates in a similar fashion, except that it sends and receives data through radio waves rather than a telephone line.

 Sending SMS

1. Insert a valid SIM card from any mobile provider into the SIM slot.

2. Connect the GSM Modem to the supplied AC-DC adapter and also to the serial port of the   PC.

 3. Select the correct COM Port in Hyper Terminal and set up the parameters as follows:

4. Power on the GSM Modem and wait for it to initialize. While waiting, we can use the following command to make sure we can communicate with the GSM Modem.

AT <ENTER>

The GSM Modem should respond with “OK”.

5. Once it’s ready, the following response will be received from the modem.

Call Ready

6. Now we can start sending the AT command to the GSM Modem. Start by configure the modem to use Text Mode instead of PDU mode for the SMS. This mode allows us to send SMS using AT commands without the need to encode the binary PDU field of the SMS. Use the following command to put the modem in text mode and it should respond with “OK”.

AT + CGMF = 1 <ENTER>

7. After that, we can send the SMS message with the following command:-

AT + CGMS " 0135219644" <ENTER>

8. Replace the above phone number with your own number. The modem will respond with:-

<

9. We can now type the message and send the message using the <CTRL+Z> key.

TEST <CTRL + Z>

10. After few seconds, the modem will respond with the message ID of the message, indicating that the message has been sent correctly.

+CMGS:49

AT Commands to send a SMS

11.  Text that receive from mobile phone. DONE !