Single PS/2 port or special case wiring ?

[chriscalvert]

The last 10 motherboards I have bought have annoyed me by having a single PS/2 port because, for a variety of reasons, it would have made my life much simpler to have had two ports.
Now my reading on the internet and the manuals would seem to indicate that you can use the port for EITHER a keyboard or a mouse but not both.
A normal Y splitter doesn't work but I have seen reference to a "special" Y splitter that appears to have been common some years ago and that has slightly different wiring inside it (it assumes that two of the wires inside the port itself are connected differently and this will allow both keyboard and mouse to be used together. Basically data and clock for one PS/2 device, the mouse, are routed to pins 2 and 6 inside the plug to the motherboard where they will be rerouted to the second PS/2 port).

I have a copy of this wiring but before cobbling one up or trying to buy an original I wonder if anybody can confirm or deny whether the Gigabyte PS/2 port will allow this special case. Or have they crippled the board by genuinely only allowing a single connection ? I assume that if the special case is allowed that if you plug in either the keyboard or mouse normally that the BIOS would sort out which is which and either would function.

 

[John_VanKirk]

Hi there,

The PS/2 connectors are still found on MB's for access to the BIOS before the USB driver is installed but they require a dedicated IRQ and are not hot swappable. There were some early combination connectors that used the additional nc 2 pins so data could be transmitted independently. The Mouse and Kyb connectors are exactly alike, using the mini DIN connector, but if you use a Y adapter, the data from both peripherals are on the same pin, which doesn't work.

Even if you find an older IBM Y connector, it won't work unless the MB Female connector is specifically wired for both devices. I checked on the latest GB G67A-UD7 high end MB and it says "for either a Mouse OR KYB". Won't work with a splitter.

As you know, most mice or keyboard, and combination wireless devices are all using the universal USB ports now.
They are faster, and safer since you can't inadvertantly plug in or pull our the older PS/2 device and run the real risk of killing the super I/O chip.

Here is a good article regarding the combo PS/2 connections:
http://www.burtonsys.com/PS2_keyboard_and_mouse_mini-DIN-6_connector_pinouts.html

Hope that's helpful

 

[Motopsychojdn]

Maybe an odd one,
but had you thought of putting 'two ps2 ports' onto your list of criteria for motherboard selection?
or has it just worked out that the boards you've wanted only had the one?
Moto

 

[chriscalvert]

I found the older wiring for the "special" Y connector at burtonsys.com.

I accept that modern mice etc probably are all USB now but my work is a mixture of old and new and servers and my customers still have older KVM switches plus favourite keyboards and mice. I know we have to change (maybe a certain reluctance when we are being forced to change) but a lot of my work seems to be on the fringes and 2 x PS/2 would make it easier. Some of what I do requires the use of a keyboard and mouse before any OS has booted and I could build appropriate drivers in to the programs I want to run but that is even more work.

All the motherboards I want to use only have a single PS/2 port on them.

The whole issue of cables and small peripheral devices only worth a few dollars has sometimes held up projects worth $10-20K.

I guess it will all go away in a few years to be replaced by something else equally as annoying.

In the meantime I will stop devoting time to a possible fix and move on.

 

[Motopsychojdn]

I still have ps2>usb adaptors in my kit for either/or situations
but I appreciate the 'but I like thiiiis keyboard' problem, didn't realise they weren't your personal boards man, no offence intended but glad you got sorted out ok
Moto