Are Model M adapters useful?

[Ole Juul]

I always use a model 'M' keyboard. Now I got a new KVM which accepts ps2 and USB inputs for both keyboard and mouse. The keyboard seems to work fine on different OSs. I cannot find any suitable mouse on the market with ps2 so I am stuck with USB there. In any case, this forum is not where I expect to find the solution to the mouse not being recognized, but I am wondering if the model M could be interfering with the operation of the KVM.

There is a little problem with the keyboard in that it seems to do a key repeat on its own sometimes. I can live with that if I have to. However, that brings me to the real questions for this forum:

What is the actual need for model 'M' adapters?
What are the documented problems in not using one?

There is much talk about the M taking more power etc, but what actually happens that anybody has documented? After all, just using a dumb ps2/usb adapter works just fine without a KVM - at least in my experience. I am also using external power to the KVM, so that end of the power draw is taken care of. So, should I get this adapter to see if it makes my KVM behave better?

The KVM I got.
This is the model 'M' adapter from clickyboards.

 

[vwestlife]

I tried an IBM Model M13 keyboard -- the version with the built-in TrackPoint "eraser head mouse" -- with a cheap generic USB adapter I got from Amazon.com, and it worked fine.

 

[Ole Juul]

I tried an IBM Model M13 keyboard -- the version with the built-in TrackPoint "eraser head mouse" -- with a cheap generic USB adapter I got from Amazon.com, and it worked fine.

That's been my experience too. I don't see what people are talking about when they say there can be problems. I've tried several adapters (except the "special" model M one) and it seems to be impossible to make the model M not work on all systems - and with two different KVMs that I've tried. That's why I'm asking (in the hopes of getting a clue to my KVM issue) what the real problems could possibly be.

Edit: I just realized that I half missed the point of your post. The TrackPoint.

 

[modem7]

After all, just using a dumb ps2/usb adapter works just fine without a KVM - at least in my experience.

Unless you have opened up the adapter and found no chip, then your use of "dumb" is an assumption.

 

[modem7]

You have a hypothesis that the keyboard may somehow be stopping the KVM from recognising the mouse.
You should be able to test that hypothesis by:
1. Disconnect keyboard from KVM, keeping mouse connected; then
2. Attach a Windows based computer to KVM; then
3. Start computer.
4. When Windows starts and then presents a mouse pointer, see if you can move the pointer.

If the pointer moves, you have proven your hypothesis.
If the pointer doesn't move, then something other than the keyboard is the cause of the mouse problem.

NOTE: Your KVM appears to be 'intelligent' and therefore I expect will appear as a keyboard to the computer (even with no keyboard plugged into the KVM).

 

[Ole Juul]

Unless you have opened up the adapter and found no chip, then your use of "dumb" is an assumption.

That's a good point. I've tried a couple that worked, but I haven't paid attention to what they were. So you're right, I don't know if there's a chip in them. I hadn't actually considered that.

You have a hypothesis that the keyboard may somehow be stopping the KVM from recognising the mouse.
You should be able to test that hypothesis by:
1. Disconnect keyboard from KVM, keeping mouse connected; then
2. Attach a Windows based computer to KVM; then
3. Start computer.
4. When Windows starts and then presents a mouse pointer, see if you can move the pointer.

If the pointer moves, you have proven your hypothesis.
If the pointer doesn't move, then something other than the keyboard is the cause of the mouse problem.

NOTE: Your KVM appears to be 'intelligent' and therefore I expect will appear as a keyboard to the computer (even with no keyboard plugged into the KVM).

Thanks for the suggestion. I don't have a Windows machine handy for testing, but your logic is good and got me going to prove the hypothesis. First, I should say that I had figured that the mouse situation was most likely OS related since dmesg picks it up as ums0, yet there was no response. However, since there was also some random keyboard glitch, I thought there may also be some other problem.

Second, you caused me to fix the mouse problem. I reset the KVM and then unplugged the mouse from the USB port on the computer, and then plugged it into the KVM. It works! I had tried a number of different situations before, including adding a working Linux machine. What I didn't do was reset the KVM. I had originally plugged in a power supply to power it because the first machine to come on line was a DOS box with no mouse or USB. That may well have caused the "intelligence" in the KVM to become discombobbled. I don't know. In any case, a reset fixed the problem.

As for the keyboard repeat glitches, I'll have to wait to see about that. It hasn't happened while I've been doing this now.
Thanks M7 for getting me to this point.

I'm still interested in the main question, which is: are special adapters for the model M of any practical use. Has anybody here got any experience with them?

 

[modem7]

I'm still interested in the main question, which is: are special adapters for the Model M of any practical use.

On the page you pointed to, I see nothing there that indicates that the adapter that they are offering is specially for the model M keyboard.
From what I read on that page, the gist is: some adapters may not work with vintage keyboards, and here is one that will probably (not definitely) work.

I think you are being influenced by the ad appearing on a web site that primarily sells Model M keyboards.

 

[Ole Juul]

I think you are being influenced by the ad appearing on a web site that primarily sells Model M keyboards.

You're probably right. I thought there had been discussion here about model M compatibility, but I'm not finding much now. There are however a number of references to adapters that theoretically "don't work" on the net. They too may be influenced by the clickity guy - or perhaps written by him. In any case, from my own experience, I would say that the advertised adapter from Clickity is not worth getting.

My own situation about mouse recognitiong appears solved. I should have thought about the reset earlier. (My previous KVM didn't have one.) There's still an occasional keyboard glitch though. When I get time, I'll try another newer ps2 keyboard to see if there is any difference.

 

[Stone]

FWIW, I have about ten KVMs. But, for my tastes, they are mainly just Vs as the KM part(s) always leave(s) something to be desired. Sooner or later the mouse and/or keyboard switch will not function properly or even not function at all. So I have ended up using them as Video switches only.

 

[Ole Juul]

FWIW, I have about ten KVMs. But, for my tastes, they are mainly just Vs as the KM part(s) always leave(s) something to be desired. Sooner or later the mouse and/or keyboard switch will not function properly or even not function at all. So I have ended up using them as Video switches only.

That's interesting info. I basically need keyboard access to three computers, and a KVM is the only way to go. I've also got an ancient 4 port manual KVM in the mix, but its use is limited by serial mouse connections. Physical switching does have a certain reliability though.

As mentioned above, I will do some playing around to see if there is a more workable solution. I just tried a no-name adapter, of the kind with two PS/2 connectors going to a USB output. It has a green and a purple input. The keyboard glitches still happened. Then I tried a StarTech "USB to PS/2 Keyboard/Mouse Adapter" (model USBPS2PC) of the same configuration, except it doesn't distinguish between the two PS/2 inputs. It's been in for an hour now, and although it will take more than that to prove it's functionality, it seems to do the trick so far. I don't know if it's got a resistor or chip in it, but perhaps there is something to using a suitable adapter after all.