[jderou]

My machine interface uses the ps/2 input on the PC for the buttons on the console. I can also plug in an external keyboard, but it overrides the console buttons. I want to leave the keyboard plugged in and mount it permanently and be able to use both (without a switch).

There are splitters like this:
CBA 222 - PS/2 Keyboard Adapter (connects two keyboards into one PC keyboard port) - CyberResearch

and there are splitter like this:
$3.00 Cable en Y pour clavier et souris PS2 - SuperGadgets.ca

What kind of electronics does it take to make these splitters work (or would they work?). Would some kind of arrangement of diodes do the trick?

[pricklypunter]

The PC needs to see only 1 keyboard at a time, I suspect what you need is a KVM switch that autodetects which keyboard is being used and switches over automatically

[neilw20]

I have seen a PC with two USB keyboards and they both work at the same time. (somehow!!)

[jderou]

pricklypunter,
does someone make an automatic switching kvm? I experimented with this for a while. It seems that because the pc and keyboard are "talking" with the clock signal, switching one off and the other on is not instantaneous. This leads to a delay and missed keystrokes, unacceptable for the application. I even found another internal connector on the motherboard for a ps/2 mouse, but apparently a mouse has different pinouts.

neil, I have no usb ports. This is on an Anilam control, which is dos-based. I am 75% now leaning towards a retrofit to Mach. I am on the fence, cause it is a stable accurate machine, just lacking in the interface department.

[neilw20]

With Mach you can allocate OEM switches, and they can double keyboard hits, or be entirely separate.
Can't help much without more information about your system, and maybe some pictures.
Which of the many models of Anilam do you have?

[jderou]

It is an Anilam 3300mk.
The control panel is a matrix keyboard that sends signals into the ps/2 port of the motherboard, just as a keyboard would. unfortunately they did not include ASCII characters on the keypad, so it is either use the arrows for the on-screen character map (lame) or plug in external keyboard. Plugging in the external keyboard overrides the control panel, so both can't be used at the same time (also lame). There are several buttons on the control panel that are much better in use than a keyboard, so one has to go back and forth at times.
It may be possible to add usb to the system, but it is dos, and I don't know if it is worth getting into that headache.

[xjdubber]

if you can add usb, then add a usb keyboard. PS2 can only talk to one device at a time. You will be able to use a usb keyboard and ps2 keyboard at the same time.

[jderou]

a quick search shows that dos drivers are available, though I am sure installing them won't be a breeze. Biggest problem may be room. While there is an ISA (yes ISA) slot open, it is blocked by the motion control card. See pic below, Hard to see the port down there. The board on the left is actually this motherboard: Acqutek - JUKI-745E
It says usb support, not sure what that means. May be worth a call to them.
The board on the right (with blue pots) is the motion controller.