Abstract
This paper shows an approach for designing a system which implement a microcontroller based control module that receives its instructions and commands from a cellular phone over the GSM (Global system for mobile communication) network. The microcontroller then will carry out the issued commands and then communicate the status of a given appliance or device back to the cellular phone. This device allows a user to remotely control and monitor multiple home office appliances using a cellular phone. This system will be a powerful and flexible tool that will offer this service at any time, and from anywhere that has network coverage. Due to the fact that the combination and sequential logic circuits have more components soldered together, inflexible, more difficult to the user, and not programmable, the 8951 micro controller was chosen because it can be written to and read from and also has an internal memory which makes it to be versatile in application and user friendly. Apart from the micro controller, other electrical electronic components used include. resistors, filters, voltage regulator, transformer, rectifiers, capacitors, DTMF (Dual Tone Multi Frequency) Integrated circuit etc.