RS-449 (EIA-449) Secondary

Pin	Name	RS232	V.24	Dir	Description
1		n/a	101		Shield
2	SSR	SRR	122		Secondary Receiver Ready
3	SSD	SSD	118		Secondary Send Data
4	SRD	SRD	119		Secondary Receive Data
5	SG	SG	102		Signal Ground
6	RC	RC	102b		Receive Common
7	SRS	SRS	120		Secondary Request To Send
8	SCS	SCS	121		Secondary Clear To Send
9	SC	SC	102a		Send Common

Note: Direction is DTE (Computer) relative DCE (Modem).
Note: RS232 column is RS232 circuit name.
Note: V.24 column is ITU-TSS V.24 circuit name.