Request to Send (RTS) is generated by data terminal equipment (DTE). It indicates that the DTE has buffers to receive data from the data circuit-terminating equipment (DCE).
Clear to Send (CTS) is generated by DCE. It indicates that the DCE has buffers to receive data from the DTE.
Data Terminal Ready (DTR) is pin 20 of the Electronic Industries Association/Telecommunications Industry Association (EIA/TIA)-232 interface standard. DTR is generated by the DTE and informs the DCE that it is ready to receive an incoming call.
Carrier Detect (CD) is generated by DCE. It indicates that DCE-to-DCE communication has been established.
Data Set Ready (DSR)is pin 6 of the EIA/TIA-232 interface standard. DSR is generated by the DCE and informs the DTE that it is ready for use.
The command to place a serial interface into asynchronous mode is physical-layer async.
To specify a known modem type, enter modem autoconfigure type modem_type.
The modem autoconfigure discovery command tries to discover an attached modem.
Null modem cables cross-connect pins 2 and 3 for data transfer, TxD (transmit data) and RxD (receive data).
