Mouse/kb y-connector problem on laptop

I want to attach an external mouse and keyboard to an old laptop (Compaq
Armada 4110d). The laptop has a ps/2 connector at the back (marked KB and Mouse). The laptop works with an external keyboard or mouse individually, but when I try to use one of those convenient Y-connectors (also with individually marked connectors for KB and Mouse), the external keyboard refuses to work. When I connect JUST the keyboard to its proper connector at the cable (and leave the mouse unconnected) the keyboard doesn't work either. I'm pretty sure the splitter/cable is still OK and not damaged since it was purchased and used only about a month ago for use on
another-brand laptop.

Is there another kind of splitter that I should be using for this Compaq
laptop? I used the splitter/adapter on Thinkpad with no problems
whatsoever.

The laptop is roughly 10 years old. Currently with W98se. The laptop manual doesn't give any clue whether using external mouse/keyboard simultaneously would NOT work - except to show that the clock and data pinouts for mouse and keyboard use are exactly the same. So... would this mean that any splitter WON'T work?

Hmm.. Actually Thinkpads and Compaqs should be the ones with similar PS/2 splitters and all the rest fishy.. But yeah, the Y cable is no standard and you should ask some Compaq place what kind of splitter, if at all, you can use.

Did you try restarting the laptop while the splitter is connected?

Oh yes.. the connector/splitter was always connected and the pc rebooted each time I added or removed the mouse or keyboard. Good idea about asking a specific Compaq person.