The TEA5500 is an encoder/decoder circuit, for security systems. The system can transmit a complex code between an encoding and decoding unit by infrared radiation. The device can operate as an encoder or decoder depending on the external circuitry connected to the data input. The code is made by the 10 input pins E1 to E10 by connecting them either to ground (LOW) or to the positive supply (HIGH) or leaving them floating. This allows (3^10)-2 combinations. Two combinations are prohibited; E1 to E10 = HIGH and E1 to E9 = HIGH, E10 LOW.
