The main objective of this system is to transmit message or text through ordinary Land Line Telephone from one end (source) to another end (designation). This is get achieved by the DTMF technology. It has two sections one for editing the text and to transmit the edited text and the other section consist for receiving the text message. The system works on the DTMF technology. (Dual Tone Multiple Frequency).
It involves several steps. They are
DTMF decoding/Encoding process
ON/OFF hook detection
Displaying the message in LCD
The above process is get achieved by the microcontroller AT89S8252.Thus Microcontroller controls the whole system.