Excellent, Mangetout. And 15 meters is actually 49.2 feet, according to my computer. So I think I am going to buy a 50 foot PS/2 cable and see how that works.
I use a Logitech wireless (not bluetooth or whatever it’s called) keyboard and mouse and I have never had any problems with them. Also, they were very cheap (£20).
They make their money on volume.
Sorry, didn’t see it! That would work a bit better!
Just reporting back to say that I just tried two 15 metre PS/2 extension cables in series with a standard keyboard at one end and a PC at the other; worked just fine. That’s not to say that it will inevitably remain fine in all circumstances; I suspect the setup will be more susceptible to power supply fluctuations and noise than otherwise, and it might not even work for everybody if there’s any sort of variability from PC to PC on the amount of power the motherboard makes available to the keyboard.