DTE-to-DCE Communication

Data transfer

Transmit Data (TxD)

The DTE transmits data to the DCE.

Receive Data (RxD)

The DTE receives data from the DCE.

Ground (GRD) or pin 7

Provides the ground reference for voltage measurements.

Hardware flow control

Request to Send (RTS)

Indicates that the DTE has buffers available to receive from the DCE.

Clear to Send (CTS)

Indicates that the DCE has buffers available to take data from the DTE.

Modem control

Data Terminal Ready (DTR)

The DTE tells the DCE that it can accept an incoming call.

Carrier Detect (CD)

The DCE has established a carrier signal with the remote DCE.

Data Set Ready (DSR) or pin 6

The DCE is ready for use (a pin is not used on modem connections).