Common names: EIA-449, RS-449, ISO 4902
Secondary (auxilary) channel
 (at the Computer)
| 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.
Contributor: Joakim Ögren
  Source:
  RS449 Page at Connectivity Knowledge Platform (Made IT)
  Copyright © The Hardware Book Team 1996-2001.
  May be copied and redistributed, partially or in whole, as appropriate.
 Document last modified: 2001-06-08