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Serial mice and PS/2 KVMs

H

hargle

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minneapolis, MN
I have an 8 port KVM, all PS2 connectors. With the assistance of the AT2XT keyboard converter, I can share 1 keyboard among my entire geek collection, from my 8088's all the way up to a P4 box. It's most excellent and highly recommended.

While not exactly as important as a keyboard, I figured that having a mouse available to all my platforms would be fun too, but I'm unable to make it work. The input/outputs to my KVM are all PS2, but I'd need to hook everything up to serial on the PC side. There are differences between PS2 mice and serial mice in signaling, and only certain mice work with those ps2->serial adapters. I assume going though a KVM is only going to make matters worse.

Has anyone done it before?

Mouse----->[PS/2 KVM]----->serial adapter--->5150?

If it works for you, can you supply me with the mouse model/part number so I can hunt for one that works?
 
Hargle,

I think those adapter things are just wiring adapters - they have no intelligence. The mouse senses what protocol is in use and chooses PS/2 vs. serial based on what it sees. So it is going to choose what to use based on what the KVM looks like, not the downstream PC.

It's possible that the adapter is keyed in such a way as to force the mode on the mouse. Even so, that still wouldn't work in your diagram above.


Mike
 
Also didn't serial mice generally stop working if disconnected (obviously, but I mean even when re-connected, until a reboot)?

I seem to remember having problems with mice through KVMs even where it was all one brand, for example with Proliant 5000's and similar.
 
Belkin makes (or used to make) KVM that would sumilate a serial mouse (and has serial ports) while letting you use a PS/2 mouse at the console (Model F1D104). Older units like the F1D066 would make you use both serial and PS/2 mice at the console.

All the XT class (8088/8086) machines need a XT keyboard, not sure how well a KVM would work with XT and AT machines using a keyboard like a model M that switches between the modes.
 
pearce_jj said:
Also didn't serial mice generally stop working if disconnected (obviously, but I mean even when re-connected, until a reboot)?
Click to expand...

I believe you are talking about PS/2 mice (plugged into a PS/2 port). If they are not detected when the machine starts up then they won't work at all without a re-boot. I am fairly certain that serial mice don't have this issue.

@Hargle - Do you still have any of those keyboard adapter kits left?
 
Unknown_K said:
All the XT class (8088/8086) machines need a XT keyboard, not sure how well a KVM would work with XT and AT machines using a keyboard like a model M that switches between the modes.
Click to expand...
yeah, we've worked around that with a fun little PCB project, the AT2XT keyboard converter:http://www.vintage-computer.com/vcforum/showthread.php?15907.

I'm wondering if we need a PS22Serial converter project too?

Hargle - Do you still have any of those keyboard adapter kits left?
Click to expand...
Yep! I think I have 4 or 5 left. $10 each and $3 for shipping in the USA
 
Unknown_K said:
Belkin makes (or used to make) KVM that would sumilate a serial mouse (and has serial ports) while letting you use a PS/2 mouse at the console (Model F1D104). Older units like the F1D066 would make you use both serial and PS/2 mice at the console.

All the XT class (8088/8086) machines need a XT keyboard, not sure how well a KVM would work with XT and AT machines using a keyboard like a model M that switches between the modes.
Click to expand...

XT computers used XT keyboards (typically Model Fs, but there was the Model F AT) which have a different protocol.
AT and PS/2 computers all use the same protocol; that's why you can have SDL cables with either the DIN or mini-DIN connectors (same signal regardless of cable style).
KVM switches might not like the fact that model Ms pull loads of power (like some of my newer computers), however, it otherwise should be fine.
If it's a Model F XT, then it won't work at all unless you build your own adapter to translate. You could actually fry something by hooking up an XT keyboard.
 
Currently I have 3 different model Belkins in use (yes I have a hell of a lot of machines set up and running). Being able to run older machines with serial port mice on a KVM that uses a PS/2 MS Optical mouse is nice. My newer gaming rigs run Belkin SOHO KVM's that do sound as well.
 
My Linksys 4-port works great with my Model M and a Logitech PS/2 mouse from 1994. If I ever need a serial mouse the adapter works great there.

I'm fairly certain that as long as to switch you hit a button the switch itself you'll be good. I know my new 4-port Iogear switch does not like my Model M connected to a USB to PS2 adapter and then into the switch, computers can type but I can't switch between them D:.
 
EverythingIBM said:
AT and PS/2 computers all use the same protocol; that's why you can have SDL cables with either the DIN or mini-DIN connectors (same signal regardless of cable style).
Click to expand...

Every time I have plugged an AT machine into a PS/2 KVM (with an din-mini dim adapter) I have blown out the keyboard fuse on the motherboard. Any idea why this happens?
 
lutiana said:
Every time I have plugged an AT machine into a PS/2 KVM (with an din-mini dim adapter) I have blown out the keyboard fuse on the motherboard. Any idea why this happens?
Click to expand...
The particular adapter you have may be designed for a purpose other than PC family keyboards.
 
I don't know if this is the case for you, but AT keyboards do draw quite a bit more current than PS/2 ones. I'm guessing that you're using the KVM on a PS/2-era or later motherboard. If that's the case, you might consider supplying the keyboard from an external supply.
 
modem7 said:
The particular adapter you have may be designed for a purpose other than PC family keyboards.
Click to expand...

I don't think lutiana would use anything but an AT to PS/2 adapter (besides, it's an interface adapter, not electrical).
Haven't seen a DIN/mini-DIN adapters that did something more than change the two interfaces; and if they did, it would cost a lot of money, be considerably larger, and, by that point, anyone would know it wouldn't be meant for keyboards.

lutiana said:
Every time I have plugged an AT machine into a PS/2 KVM (with an din-mini dim adapter) I have blown out the keyboard fuse on the motherboard. Any idea why this happens?
Click to expand...
Model Ms and Model F AT keyboards draw a lot of power (it has been known for them to damage PS/2 ports on computers); I assume you mean the KVM gets the blown fuse? Rather than the AT machine?
Did you try hooking up something different like a fujitsu peerless?

EDIT: or do you mean just hooking up the computer to the KVM switch without a keyboard? In which case, the AT computer could be drawing a lot of power too. That's why newer computers don't like older keyboards due to the higher power requirements; likewise, the ports on the older machines carry a stronger voltage.
 
EverythingIBM said:
I assume you mean the KVM gets the blown fuse? Rather than the AT machine?
Did you try hooking up something different like a fujitsu peerless?
Click to expand...

No, I meant the fuse in the AT computer itself, and yes it was just a DIN-miniDin adapter. Basically it was:

PS/2 MS Natural Keyboard ---> 4 port KVM ---> Adapter ---> AT Computer

Blew out the fuse on both my 486 and 386 so I gave up trying.
 
lutiana said:
No, I meant the fuse in the AT computer itself, and yes it was just a DIN-miniDin adapter. Basically it was:

PS/2 MS Natural Keyboard ---> 4 port KVM ---> Adapter ---> AT Computer

Blew out the fuse on both my 486 and 386 so I gave up trying.
Click to expand...

Sounds like something is shorted. I assume you've tried with a keyboard directly connected to the adapter (meaning the adapter is known to be good)?

I have a similar setup: PS/2 keyboard ---> KVM (Belkin F1DS104JEA) ---> PS/2 to AT adapter ---> Wang 286

This works OK with one exception. When I start the Wang it emits a long beep and there is no image on the monitor. I have to shut it down after a few seconds and then start it again for it to work. This is really odd and I hope someone can explain it?
 
Krille said:
Sounds like something is shorted. I assume you've tried with a keyboard directly connected to the adapter (meaning the adapter is known to be good)?
Click to expand...
I agree. It sounds like something improperly connected.
Here is a list of possibilities that I can think of:

* DIN/mini-DIN adapter is of wrong type for purpose (wrong pins are being interconnected);
* DIN/mini-DIN adapter is of correct type but faulty;
* KVM faulty;
* Computer port (via adapter) is attached to keyboard port of KVM (results in both computer and KVM pushing 5 volts onto same wire).

Krille said:
I have a similar setup: PS/2 keyboard ---> KVM (Belkin F1DS104JEA) ---> PS/2 to AT adapter ---> Wang 286
This works OK with one exception. When I start the Wang it emits a long beep and there is no image on the monitor. I have to shut it down after a few seconds and then start it again for it to work. This is really odd and I hope someone can explain it?
Click to expand...
I have the DVI version of the F1DS104JEA. Although it appears to work okay without its external power supply connected, the user manual does not indicate that the power supply is optional. Do you have the power supply connected?
 
modem7 said:
I have the DVI version of the F1DS104JEA. Although it appears to work okay without its external power supply connected, the user manual does not indicate that the power supply is optional. Do you have the power supply connected?
Click to expand...

Yes. How do you power yours if not by the power supply?

Also, I know that the KVM immediately detects the computer because the indicator on the front stops blinking as soon as I power on the Wang.
 
Some are powered by the systems connected themselves. My iogear 4-port is, my mom's 2-port Belkin is and my 4-port Linksys also happens to be powered by the computer(s) connected to them.
 
modem7 said:
I agree. It sounds like something improperly connected.
Here is a list of possibilities that I can think of:

* DIN/mini-DIN adapter is of wrong type for purpose (wrong pins are being interconnected);
* DIN/mini-DIN adapter is of correct type but faulty;
* KVM faulty;
* Computer port (via adapter) is attached to keyboard port of KVM (results in both computer and KVM pushing 5 volts onto same wire).

I have the DVI version of the F1DS104JEA. Although it appears to work okay without its external power supply connected, the user manual does not indicate that the power supply is optional. Do you have the power supply connected?
Click to expand...
It has absolutely nothing to do with the mini-DIN adapter. It's a standard 6-pin MINI-din to 6-pin DIN. There's only one kind of interface.
If the wires of the mini-DIN adapter were changed, it would be a different number of pins (like a 7 pin mini-DIN which wouldn't fit), or the two devices being connected wouldn't be using the same signal... such as MIDI and PS/2.

The issue is either the AT computer or KVM switch. I'm positive it's the computer drawing too much power.
 
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