Quoted from BBalasz:

All you have to do is connect the PCs, and turn them on. No configuration or whatsoever is needed, because a serial cable is INDEPENDENT from a network card. No IPs here.

Now, go to the Age of Empires multiplayer menu. There you should see something like 'Serial Connection for DirectPlay'. Now, click OK, and create a game. Upon creating, you will be asked for information on the communications port (a hardware port, not an IP port! ), baud rate, stop bits, parity and flow. Make sure that the serial cable is connected to the COM1 port of your PC. If not, select a different COM port, the one you plugged the cable into. Now, join with the other PC. Upon clicking 'show games'. You will be asked the same questions. Check that the port is correct (the cable is plugged into the correct place), and click ok. Now you should see the game and you should be able to join.

Note, once again: Do not use TCP/IP connection, or whatsoever. Use Serial connection for DirectPlay. Serial/Parallel cables work even if you have NO network card. 9-pin serial plugs use ports that are (almost always) designated COM ports and the parallel ports use the LPT ports (the old-fashioned printer port).

This connection method is very primitive, but very effective for two player gaming, and it even works. Because it is so 'ancient', I believe you don't even have to disable most firewalls, they do not track it. Even though it is primitive, it works perfectly for Age of Empires, I know

[This message has been edited by aoe_scout (edited 01-01-2014 @ 06:16 PM).]