# EIA-449 (RS-449) Secondary

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)

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May be copied and redistributed, partially or in whole, as appropriate.
Document last modified: 2001-06-08