Turning on computer using communication port

I am working on something that would require a computer to be turned on "remotely" but still within reach in the same building. I did some reading about WOL (Wake On LAN) and would like to know if there's any other way to turn computer on either through a USB cable, serial RS232 port or some other existing method that I haven't come to know yet.

I've also read about turning on power supply by connecting one of the pin which will in turn power up the said computer. I am open to ideas so please throw in your suggestions.

Solution 1:

If you've got a bit of budget one of the simplest solutions is a remote controlled power supply. Something like these products from Dataprobe. They are extremely useful and pretty easy to setup. Most computers now days have an option in the BIOS to boot as soon as there is power, so this offers a very simple solution to your problem.