An IC that is similar to a common RS-232 transceiver except that the RS-232 interface is multiplexed with an LVTTL interface (TTL is acceptable too). We’d like the serial port on the product to support both RS-232 and LVTTL.
The important thing is that the RS-232/LVTTL interfaces are going to the same pins on the “DB9” connector, therefore a traditional mux does not work unless it is designed to tolerate RS-232 voltage levels.
