COM Port TX - Communications TX Configuration.Some early radios do not support switching TX/RX via CAT commands. This option allows you to configure a COM port pin to carry out this function.
A list of radios without CAT switching is shown.
None - No port pin will be used.
RTS - Request To Send pin will be used. This is Pin 7 of a DB9 connector.
DTR - Data Terminal Ready pin will be used. This is Pin 4 of a DB9 connector.
DTR + RTS - Both Data Terminal Ready and Request To Send pins will be used for the TX/RX switching function.