http://www.chami.com/tips/windows/020897W.html

How to create a Null Modem Cable

If you want to use Windows 95's Direct Cable Connection, or need to create a "Null Modem Cable" for some reason, here are the pin connections for 9-pin and 25-in serial ports.

=====================      =====================
|      9 Pin        |      |     25 Pin        |
=====================      =====================
| Port #1 | Port #2 |      | Port #1 | Port #2 |
+-------------------+      +-------------------+
|    2    |    3    |      |    2    |    3    |
|    3    |    2    |      |    3    |    2    |
|    4    |   6,1   |      |    4    |    5    |
|    5    |    5    |      |    5    |    4    |
|   6,1   |    4    |      |   6,8   |   20    |
|    7    |    8    |      |    7    |    7    |
|    8    |    7    |      |   20    |   6,8   |
=====================      =====================