9-to-25 Pin RAS Null Modem Cabling

 Last reviewed: March 25, 1997
Article ID: Q108296
The information in this article applies to:
  • Microsoft Windows NT operating system version 3.1
  • Microsoft Windows NT Advanced Server version 3.1
  • Microsoft Windows NT Server version 4.0
  • Microsoft Windows NT Workstation version 4.0

SUMMARY

The Windows NT Remote Access Help file includes tables showing the correct wiring of a null modem cable for use with RAS. The two tables included show the correct wiring for a 9-pin null modem cable and a 25-pin null modem cable. The following table contains the proper null modem wiring that must be used when the cable connects a 9-pin serial port to a 25-pin serial port. 

   25-pin Connector       to    9-pin Connector
   ----------------------------------------------------
   2 (transmit data)      <->   2 (receive data)
   3 (receive data)       <->   3 (transmit data)
   4 (request to send)    <->   8 (clear to send)
   5 (clear to send)      <->   7 (request to send)
   6,8 (data send ready,
        carrier detect)   <->   4 (data terminal ready)
   7 (ground)             <->   5 (ground)
   20 (data terminal
       ready)             <->   6,1 (data send ready,
                                      carrier detect)

Additional query words: prodnt nul
Keywords : kbnetwork ntras NTSrvWkst
Version : 3.1 4.0
Platform : WinNT

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Last reviewed: March 25, 1997
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