PS/2 Y Splitter on Single PS2 Port

A PS/2 Y splitter is a clever little adapter or cable which lets you plug a PS/2 keyboard and PS2 mouse into a single PS/2 socket in a computer. This is especially useful on laptop or notebook computers which typically only have one PS2 socket.

Although you can get PS/2 to USB adapters there may be circumstances where you would like to connect both devices to the same socket, for example: if your laptop doesn’t have any USB ports; or you want to connect it to a KVM switch which lets you share keyboard, mouse and monitor between two or more computers but it only supports PS/2 mice. I use this with a laptop and my desktop computer using a Belkin 2-Port KVM Switch.

PS2 Y splitters are very cheap and you should be able to pick one up from your local computer store or an online merchant fairly easily. They work in most laptops without any problems.

Sometimes they do not appear to work. You plug both the keyboard and mouse into the Y splitter and you can use the keyboard but not the mouse. The trackball or trackpad on the laptop still works but the mouse doesn’t, and rebooting has no effect.

This is known problem with some Belkin PS/2 Y Splitters and may also be a problem with other brands as well. I bought a cheap unknown brand splitter and it had this same problem. It turns out that the adapter is moulded incorrectly and the little mouse and keyboard icons are in the wrong position. Try swapping them around and then reboot to see if that works.

If you are still experiencing problems after this, try another mouse and/or keyboard to see if that solves the problem (assuming you have spares, that is). Remember that depending on your operating system you will need to reboot between attempts as PS/2 devices are generally not hot-swappable (ie you can’t unplug and plug it back in and expect it to keep working). If it still doesn’t work I would suggest returning it to your retailer.

PS/2 Y Splitter
Cable PS2 Y
Splitter Adapter
Examples of a PS/2 Y Splitter

Generic Y splitters should work on all laptops that support this functionality but sometimes they do not, and you may need to buy a specific hardware addon from the laptop vendor. Sometimes cheaper hardware can also present you with problems and it may pay to spend a little more. Talk to your retailer and they should be able to give you the best advice.

Some laptops/notebooks and brands that Y splitters are know to work on are as follows:
– Toshiba TE2100
– Toshiba Satellite series
– Toshiba 2750DVD
– Compaq EVO
– Compaq Armada
– NEC
– AST
– Gateway 2000
– Winbook
– Dell
– IBM Thinkpad
– HP Omnibook
– Dell Inspiron (the faq for these states they are not actually supported but I’ve read a newsgroup post that suggests they will work but with some “annoyances”)