EIA-449 (RS-449) Secondary

From HwB

Common names: EIA-449, RS-449, ISO 4902
Secondary (auxilary) channel



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


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