What are monitor receivers, and what would I do with one?
These are noninverting RS-232 receivers (see ICL3241-45) that never disable. A monitor receiver shares an input with a regular inverting receiver, allowing the regular receiver to disable during shutdown while the monitor receiver continues to scrutinize the RS-232 input for activity. An event (such as a ring indicator) can still be acted upon, via the monitor receiver, even in powerdown.
