Sun Microsystems 220R service manual Serial Port a and B Connector Diagram Serial Port Signals

A.2.1 Serial Port A and B Connector Diagram

A.2.2	Serial Port Signals
	Pin	Mnemonic	Signal Name	Description
	1		Not	None.
			Connected
	2	TXD	Transmit	Used by the data terminal equipment (DTE)
			Data	to transmit data to the data circuit
				equipment (DCE). Except when control data
				is being sent, RTS, CTS, and DCD must be
				ON for this line to be active.
	3	RXD	Recive Data	Used by the DCE in response to received
				data from the DTE.
	4	RTS	Ready to	Used by the DTE to condition the DCE for
			Send	data transmission. The transition to ON
				directs the DCE to go into transmit mode.
				The transition to OFF directs the DCE to
				complete the transmission.
	5	CTS	Clear to send	Used by the DCE to indicate if it is ready to
				receive data from the DTE. When CTS, DSR,

RTS and DTR are ON, the DCE is ready to transmit data received from the DTE across the communications channel. When only CTS is ON, the DCE is ready to accept dialing or control signals only. When CTS is OFF, the DTE should not transfer data across TXD.

Connector Signal Descriptions 233