The HT12D is a 2^12 decoder in 18 pin DIP package. This decoder is a series of CMOS LSIs for remote control system applications. It is paired with Holtek’s 2^12 encoder. For proper operation, a pair of encoder/decoder with same number of addresses and data format should be chosen. The decoder receives serial addresses and data from programmed 2^12 encoder that is transmitted by a carrier using an RF or an IR transmission medium.
It compares serial input data three times continuously with its local address. If no error or unmatched codes are found, the input data codes are decoded and then transferred to output pins. The HT12D is capable of decoding information that consists of N bits of address and 12 N bits of data.