Ht12E and HT 12D are popular encoder and decoder ic?s generally used with rf434 MHz module. It is easily used to create wireless device with 4 bit output. The HT12E encoder is designed for remote control system applications. It will interface to RF transmitter modules to create a secure single or multiple channel RF remote control transmitter. The oscillator is configured simply with the addition of a resistor. It is capable of encoding information which consists of N address bits and 12-N data bits. Each address/data input can be set to one of the two logic states and The HT12D decoder is a CMOS LSI for remote control system applications. It will interface to RF receiver modules to create a secure single or multiple channel RF remote control receiver. The decoder receives serial addresses and data from a programmed encoder that are transmitted by a carrier using an RF or an IR transmission medium. The decoder compares the serial input data three times continuously with its local addresses.