What are Open Collector Outputs? How can I replace them?
• Open collector outputs are an older system using a single output transistor to bring the output to zero volts, then a “pull up” resistor wired to V+ to bring the voltage to the high level. They produce square waves like modern line driver outputs, as long as the cable is not too long. Open collector outputs can be replaced by modern line driver outputs; be sure to remove any external or internal pull-up resistors remaining in the circuit.
