Hey...Sarah is Back!
Does anybody know if an external RS-232 serial modem will work with only 3 pins (Tx, Rx, Gnd) implemented on the serial interface? If yes, will modem features like auto-answer work even though the ring indicator line isn't implemented?
No. You need other signals like CTS, RTS, DCD, etc. Having Tx, Rx and Gnd is not an RS-232 standard.