This encoder can generate up to 19,683 codes from 9 address lines by detecting 1,0, or open circuit. To initiate the transmit sequence, pin 14 should be pulsed low. The encoder will now output on pin 15 a data stream representing the condition on each of the address/data pins in turn and then repeat the operation, so that two complete identical words are transmitted. If pin 14 is held low, the output will be continuous, otherwise two identical words are output for each pulse on pin 14. A 1 is transmitted as two long pulses, a 0 as two short pulses, and an open circuit as a long pulse followed by a short pulse.
The device is constructed in CMOS and all characteristics are as the standard 4000B devices. If an external oscillator is used, it should be connected to pin 11 and pins 12 and 13 left open. The output can drive rf, ultrasonic or infrared transmitters.