kikendo wrote on 2025-06-11, 21:16:

I am looking to get a KVM but the catch is that I need to connect a serial trackball to it.
I mostly see PS/2 connectors for both keyboard and mice.

Does such a thing exist? Alternatively, are there adapters to use serial mice on PS/2 ports? All the info I find is to go the other way around (and I have plenty of PS/2 to serial adapters)

I'm pretty sure there are adapters for serial(mouse) to PS/2(port) - I thing I had one back in the day...

But you have to be careful... When serial was still a common option, lots of vendors sold mice with an included
"adapter" - but most of these were not general purpose/signaling converters ... Internally t he mouse could do
either serial or PS/2 ... and recognized the adapter to convert the type of signalling - all the adapter did was to
re-arrange the pins to a different connector,

DaveDDS wrote on 2025-06-11, 21:27:

I'm pretty sure there are adapters for serial(mouse) to PS/2(port) - I thing I had one back in the day...

Those adapters only worked for mice that could speak both serial and ps/2. They just connected wires. They didn’t convert ps/2 to serial. They are not going to make a PS/2 KVM work as a serial mouse.

Some old KVM's support serial like Belkin OmniView Pro KVMs, such as the F1D104 /F1D066
As well as some enterprise level KVM's like Aten, Compaq, etc.
But most don't.

Unless your trackball supports the PS2 protocol cheap "passive" PS2 to serial adapters won't work due to the type of signalling as DaveDDS mentions
"Intelligent" adapters exist such as the one below, which will convert the serial signal into PS2, but people report this also introduces lag
https://www.serdashop.com/PS2TOSERIAL

I ended up going with a 2 mouse setup. PS2 mouse connected to the KVM and a serial mouse plugged direct to my 1 PC that lacks a PS2 mouse port.

douglar wrote on 2025-06-12, 03:17:

DaveDDS wrote on 2025-06-11, 21:27:

I'm pretty sure there are adapters for serial(mouse) to PS/2(port) - I thing I had one back in the day...

Those adapters only worked for mice that could speak both serial and ps/2. They just connected wires. They didn’t convert ps/2 to serial. They are not going to make a PS/2 KVM work as a serial mouse.

That is kinda what I said in the following "But you have to be careful..." paragraph...

But I do recall at one time having an "active" adapter that actually converted the protocol...
but I'm pretty sure those were VERY rare!
(wouldn't be hard to make one if you really need it and are comfortable building little microprocessor things)

chinny22 wrote on 2025-06-12, 03:39:

I ended up going with a 2 mouse setup. PS2 mouse connected to the KVM and a serial mouse plugged direct to my 1 PC that lacks a PS2 mouse port.

Maybe I was misunderstood due to bad wording, I apologize.

I want to use my trackball which has a serial plug at the end with my computers, but all my computers have PS/2 mice input too, so I don't need the KVM to output serial, I need the KVM to take a serial mouse for input.
I have no idea if my trackball supports PS/2 via serial, it's the original Logitech Trackman.

kikendo wrote on Yesterday, 15:49:

Maybe I was misunderstood due to bad wording, I apologize. […]
Show full quote

chinny22 wrote on 2025-06-12, 03:39:

I ended up going with a 2 mouse setup. PS2 mouse connected to the KVM and a serial mouse plugged direct to my 1 PC that lacks a PS2 mouse port.

Maybe I was misunderstood due to bad wording, I apologize.

I want to use my trackball which has a serial plug at the end with my computers, but all my computers have PS/2 mice input too, so I don't need the KVM to output serial, I need the KVM to take a serial mouse for input.
I have no idea if my trackball supports PS/2 via serial, it's the original Logitech Trackman.

it sounds like youll have to get a ps2 to serial adapter? though ive seen the reverse

kikendo wrote on Yesterday, 15:49:

Maybe I was misunderstood due to bad wording, I apologize.

I wouldn't say so ... it seemed pretty obvious (to me at least) that you wan to use your trackball on multiple
systems ... but it's a serial device, and you only have been able to find PS/2 KVMs.

twiz11 wrote on Yesterday, 15:59:

it sounds like youll have to get a ps2 to serial adapter? though ive seen the reverse

It's one of those "not specific enough" things ...

Does "Serial to PS/2 adapter"
mean:
- Adapts a device producing a serial protocol to a computer requiring a PS/2 protocol
or:
- Adapts a computer requiring serial protocol to a device producing PS/2 protocol

I would tend to think of an adapter as input -> output ... and consider mice to be input sources,
and a PC to be the destination (although technically the signaling can be bidirectional)

I do vaguely recall that I had an active one a long time ago that would convert a serial mouse to
a PS/2 computer - but no idea if it's still a thing.

Seems like this has become a word salad of conversions. In brief: I want to connect my SERIAL trackball to a KVM that outputs PS/2 or SERIAL to my computers

kikendo wrote on Yesterday, 16:54:

Seems like this has become a word salad of conversions. In brief: I want to connect my SERIAL trackball to a KVM that outputs PS/2 or SERIAL to my computers

I'd suggest getting a KVM that does PS/2 and then use a VIP-327-SP to connect your serial mouse to the KVM.

https://www.vetra.com/327text.html

douglar wrote on Yesterday, 17:14:

I'd suggest getting a KVM that does PS/2 and then use a VIP-327-SP to connect your serial mouse to the KVM.

https://www.vetra.com/327text.html

That's so expensive it's not worth it.
I guess it's time to get a less pretty, PS/2 trackball 😜

kikendo wrote on Yesterday, 20:25:

douglar wrote on Yesterday, 17:14:

I'd suggest getting a KVM that does PS/2 and then use a VIP-327-SP to connect your serial mouse to the KVM.

https://www.vetra.com/327text.html

That's so expensive it's not worth it.
I guess it's time to get a less pretty, PS/2 trackball 😜

Have you considered using a simple serial port switch box/selector for the trackman in addition to a KVM ?

Also, what model do you have? I have one of these http://www.tcocd.de/Pictures/Peripheral/Logit … ch/tcd26f.shtml , but use a newer marble (red ball) variant most of the time.

darry wrote on Yesterday, 21:15:

Also, what model do you have? I have one of these http://www.tcocd.de/Pictures/Peripheral/Logit … ch/tcd26f.shtml , but use a newer marble (red ball) variant most of the time.

As I mentioned before, it's the very first Trackman that I have. it is often found in serial version, and that's what I got.
Maybe I'll get a PS/2 one if I can find and afford it.

kikendo wrote on Yesterday, 21:37:

darry wrote on Yesterday, 21:15:

Also, what model do you have? I have one of these http://www.tcocd.de/Pictures/Peripheral/Logit … ch/tcd26f.shtml , but use a newer marble (red ball) variant most of the time.

As I mentioned before, it's the very first Trackman that I have. it is often found in serial version, and that's what I got.
Maybe I'll get a PS/2 one if I can find and afford it.

Sorry, if I was unclear, I meant the model number. There have been a few Trackman products over the years, and it wasn't all that clear to me which one was the first and when it was released (mine seems to be from the mid 1990s). If you have a link you could share to an at least relatively authoritative and comprehensive source of information on the chronology of Logitech Trackman products, it would be helpful, IMHO.
EDIT: This site, which I linked to, http://www.tcocd.de/Pictures/Peripheral/Logit … /Logitech.shtml is nice but is far from complete. There are at least 2 products named "Trackman Stationary mouse", one of which is natively serial, and I suspect you have a squarer looking and likely older (1989ish) one also named "Trackman Stationary mouse", which I believe might be the original model ( T-AA1-4MD might possibly be the ADB variant of it). EDIT2: Most likely model T-CA1-9F , assuming https://en.wikipedia.org/wiki/List_of_Logitech_products is accurate on that point (it definitely is not exhaustive).

As for the serial switch box option I had mentioned, something like this https://www.industrialautomationparts.com/pro … 4-port-manual-1 (an example, not an endorsement or recommendation) should allow you to switch a serial mouse or trackball between multiple computers easily, if not automatically through your KVM switch.

That being said, I agree that getting a PS/2 trackball would be simpler, possibly cheaper and more seamless.

Is it serial only or would it work with a converter like this Kensington Expert Mouse Trackball Model #64215 that is for sale on ebay?

douglar wrote on Yesterday, 22:41:

Is it serial only or would it work with a converter like this Kensington Expert Mouse Trackball Model #64215 that is for sale on ebay?

The attachment IMG_2837.jpeg is no longer available

Assuming OP has a T-CA1-9F (I suspect the 9F part is likely not printed on the sticker), it would be a serial only mouse. A passive adapter/converter would not work.

EDIT: AFAICT, there are Inport bus, ADB (Mac and possibly IIGS) and serial variants of that model.

darry wrote on Yesterday, 22:17:

Sorry, if I was unclear, I meant the model number. There have been a few Trackman products over the years, and it wasn't all that clear to me which one was the first and when it was released (mine seems to be from the mid 1990s).

Ah my bad!
The trackball says: T-CC2-9F
So, this one: http://www.tcocd.de/Pictures/Peripheral/Logit … ch/tcc29f.shtml

Yeah, I am thinking trying to source a PS/2 version is the only way to go here.

Here is a picture of a t-cc2-9f with a passive adapter. Maybe it doesn’t work, but it sure looks legit. The plastic looks like it’s from Logitech.