The HT12E encoders are a series of CMOS LSIs for remote control system applications. They are 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. The programmed addresses/data are transmitted together with the header bits via an RF or an infrared transmission medium upon receipt of a trigger signal. The capability to select a TE trigger on the HT12E or a DATA trigger on the HT12A further enhances the application flexibility of the 212 series of encoders. The HT12A additionally provides a 38kHz carrier for infrared systems.
The HT12D decoders are a series of CMOS LSIs for remote control system applications. They are paired with Holtek s HT 12E series of encoders (refer to the encoder/decoder cross reference table). For proper operationa pair of encoder/decoder with the same number of addresses and data format should be chosen. The decoders receive serial addresses and data from a programmed HT 12E series of encoders that are transmitted by a carrier using an RF or an IR transmission medium. They compare the serial input data three times continuously with their local addresses. If no error or unmatched codes are foundthe input data codes are decoded and then transferred to the output pins. The VT pin also goes high to indicate a valid transmission. The HT 12D series of decoders are capable of decoding informations that consist of N bits of address and 12N bits of data. Of this seriesthe HT12D is arranged to provide 8 address bits and 4 data bitsand HT12F is used to decode 12 bits of address information.