Sms based relay operation

Hi,

I need help with the following:

I am creating a product wherein a person can control electrical appliances via remote SMS.

I want to SWITCH ON & SWITCH OFF electrical appliance with remote sms.

Here I am using four hardware:

1. A tubelight as electrical appliance.
2. Microcontroller AT89S52 of 8051 Family to intrepret received SMS and take action accordingly (On/Off).
3. SIM900 GSM Module to receive SMS from GSM Mobile and pass it to Microcontroller.
4. GSM Mobile Phone to send SMS.

SMS Formats:

1. "ON" to switch on.
2. "OFF" to switch off.

I have mounted the hardware properly and can ring the SIM latched on the SIM900 GSM Module.

But further I am stuck:

1. When I am sending SMS to SIM900 GSM Module ... I don't know how to pass the received SMS to Microcontroller.

2. And what shall be the format of communication between SIM900 GSM Module and Microcontroller AT89S52 of 8051 Family.

Any help, advice or guidance needed urgently.

Thx & Rgds

Nivesh Sharma - Electronics Engineer
Email: <SNIP>