# Two-Wire Modem (25-25)

This cable should be used for DTE to DCE (for instance computer to modem) connections without hardware handshaking.

(To Computer).
(To Modem).

25 PIN D-SUB FEMALE to the Computer
25 PIN D-SUB MALE to the Modem

| Female | Male | Dir
--- | --- | --- | ---
Shield Ground | 1 | 1 |
Transmit Data | 2 | 2 |
Receive Data | 3 | 3 |
System Ground | 7 | 7 |
Jumper these: |  |  |
Request to Send | 4 |  |
Clear to Send | 5 |  |
Data Set Ready | 6 |  |
Carrier Detect | 8 |  |
Data Terminal Ready | 20 |  |
Request to Send |  | 4 |
Clear to Send |  | 5 |
Data Set Ready |  | 6 |
Carrier Detect |  | 8 |
Data Terminal Ready |  | 20 |

Contributor: Joakim Ögren

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