Sun Microsystems Interface Adapter manual RS-449 Null Modem Cable, RS-449 Signals

RS-449 Null Modem Cable

TABLE B-1and TABLE B-2list the signals and names for RS-499 and X.21 circuits.

TABLE B-1	RS-449 Signals
Circuit	Name	Direction
TxD	Transmit Data	To DCE
RxD	Receive Data	From DCE
TxC	Transmit Clock	To DCE
TxCI	Transmit Clock In	From DCE
RxC	Receive Clock	From DCE
RTS	Request to Send	To DCE
CTS	Clear to Send	From DCE
DCD	Data Carrier Detect	From DCE
DTR	Data Terminal Ready	To DCE
DSR	Data Set Ready	From DCE
SG	Signal Ground

TABLE B-2	X.21 Signals
Circuit	Name	Direction
G	Signal Ground
T	Transmit	To DCE
R	Receive	From DCE
C	Control	To DCE
I	Indication	From DCE
S	Signal Element Timing	From DCE
B	Byte Timing	From DCE

Appendix B Null Modem Cable Requirements 31