Originally Posted By: tfabris
Most of the schematics I see indicate that I must also loopback some of the pins on the RS-232 serial plug back to other pins on the same plug.


Those other pins mostly have to do with flow control. CTS/RTS are "hardware flow control". DTR/DSR are a way of detecting whether something is ready for more data at the other end of the cable (more flow control). DCD (aka. CD) tells whether or not the cable is plugged into a compliant device, etc.

All optional, and all mostly ignored at the empeg end.