DTMF (dual tone multi frequency) based RF Remote control system is an application specific project which is used to control home appliances remotely by using telephone lines
Telephone lines that maybe found in your house may be used not only for making calls but also for other purpose like home automation, remote device control. To make it possible there is an interface between phone line and microcontroller system needed.
This DTMF extension is universal module that can be connected to any microcontroller platform. It detects DTMF tones and decodes them to binary digits that can be easily read by microcontroller, which can decide what tasks to perform.
The system uses a compact circuitry build around flash version of P89C51 Microcontroller with a non-volatile memory. Program is developed using Embedded C and compiled using SDCC tool. Flash magic is used to load programs into microcontroller