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I'm running short of USB ports and could change my keyboard to connect via PS2.
1) Do I have to reboot to use the PS2 connection?
2) Would there be any disadvantage in using a USB flex hub?

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A few practical clarifications and options that build on and 's answers to .

PS/2 is a true legacy interface and is normally initialized only at power-on by the motherboard. That means connecting a PS/2 keyboard after the system is already running is unreliable and can sometimes fail or, in rare cases, stress the connector — plug it in before turning the machine on. PS/2 keyboards also tend to allow full n-key rollover and present as a simple, BIOS-level input device (no drivers needed for basic input), which is why some prefer them for gaming or BIOS access.

Wireless receivers and passive adapters are a different story. Most wireless USB receivers enumerate as USB HID devices only; a simple passive USB<->PS/2 plug adapter will only work if the keyboard/receiver’s internal controller actually speaks both PS/2 and USB protocols (manufacturers will either include an adapter in the box or state PS/2 support). If the receiver is USB-only, expect it to fail when forced through a passive PS/2 adapter — an active converter exists but is uncommon and usually not worth the cost.

Regarding hubs and expansion cards: an ordinary unpowered USB hub is fine for a keyboard (very little power/bandwidth used), but a powered hub is recommended when multiple bus-powered devices or external drives are attached. A PCI or PCIe USB expansion card is a solid permanent fix for host-port shortage but does require opening the case, selecting the correct slot type (PCI vs PCIe) and installing drivers if the OS needs them. For BIOS/boot-menu access with a USB keyboard, enable “USB legacy/keyboard support” in the BIOS if the keyboard isn’t responding during POST.

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Member Avatar for Rik_

1) You will have to boot it with the keyboard plugged into the ps2 port in order for it to work.
2) Nope!

Member Avatar for Member #690194

Many thanks

Member Avatar for Rik_

No problem! :)

Member Avatar for Member #690194

Follow up if I may.

If I decide to get a new wireless keyboard can I connect the 'transmitter' via a USB/PS2 adaptor and would that then need a reboot?

Member Avatar for Rik_

If the new keyboard supports ps2 connection then yes! If it doesn't support ps2 connection then nope.

With my previous post I was assuming your usb keyboard came with a ps2 adapter. If it didn't and you bought one, it may not work. Some usb keyboards support ps2, some don't. It's a bit of a lottery as it's difficult to tell if they have ps2 compatability unless it's clearly stated on the box or if they have a ps2 adapter in the box with them!

Have you thought about a usb pci card? If you are short of usb ports and have a spare pci slot then it can be useful.

Member Avatar for Member #690194

Thanks

Does the pci card involve opening the PC ?

Member Avatar for benmar

yup you have to restart after you change it....

Member Avatar for Rik_

Yup, fitting a pci card would mean opening up the computer. It's not a difficult task and you will find plenty of tutorials via google or even tutorial videos via youtube!

Member Avatar for Member #690194

Thanks

Member Avatar for Rik_

No problem! :)

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