Ch MVP Trackball

[jorgenslee]

Got today another DT225 variant. At first I thought it's a PS2 as the outer shell of the socket has the same cutout, only to realize it has different pins. I searched everywhere and I can't find the same variant of this DT225. Does anyone information on this variant? The only thing I know that the socket is mini din 8-pin but I'm not sure what protocol it handles. Also the socket is connected to the board thru 4wires.

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[Findecanor]

Maybe it is for Sun Keyboard/mouse. Like Apple keyboards, Sun keyboards had a port for a mouse, but unlike Apple's ADB which used an addressable protocol, keyboard and mouse signals used different pins.

If you have a multimeter, you could check continuity to see if Sun's pin assignment for mouse matches the four wires that go to the PCB.
The thickest lines on the PCB are probably Ground, and each switch is probably activated by shorting it to Ground. On a switch's other side there may be a pull-up resistor to +5V. The other two wires should be Mouse In and Mouse Out.

(There is a Interface recognition guide in the Wiki ... but it lacks a link from the front page. )

[jorgenslee]

Maybe it is for Sun Keyboard/mouse. Like Apple keyboards, Sun keyboards had a port for a mouse, but unlike Apple's ADB which used an addressable protocol, keyboard and mouse signals used different pins.

If you have a multimeter, you could check continuity to see if Sun's pin assignment for mouse matches the four wires that go to the PCB.
The thickest lines on the PCB are probably Ground, and each switch is probably activated by shorting it to Ground. On a switch's other side there may be a pull-up resistor to +5V. The other two wires should be Mouse In and Mouse Out.

(There is a Interface recognition guide in the Wiki ... but it lacks a link from the front page. )

Thanks, I'll check out the wiki. Never knew there was that resource here, been searching for hours for any 8pin mini din interface.

Initial checking on Sun's pin assignment turns negative as the orange wire is connected to #2 on Sun' pin assignment which is ground on their specs.

[Findecanor]

BTW, does the connector have text or a symbol embossed in the flat on the side?

[jorgenslee]

BTW, does the connector have text or a symbol embossed in the flat on the side?

Yeah, though I'm not familiar with the symbol. Kindly see below.

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Checked the wiki and I think it does not match any of them. I was thinking of NeXT bus mouse but there are many pins for it to be a matched.

Since there are only four wires, do you think it's just ps2 protocol?

[Archie]

Yeah, though I'm not familiar with the symbol. Kindly see below.

It's just manufacturer's logo: stylized "CH" letters.

[Archie]

Since there are only four wires, do you think it's just ps2 protocol?

I've never seen PS/2 or ADB devices with non-standard connectors. AFAIK MiniDIN-4 and MiniDIN-6 were integral part of these standards.

As for yours, it looks to me like CD-i pointing device connector (kind of serial):

[Polecat]

I'm not familiar with that specific trackball, but if it's from the '80s or early '90s I would guess it uses bus mouse protocol. Logitech, Microsoft, and others used that interface for a while, and it did work through an 8 pin mini-DIN. The associated PC card plugged into an 8 bit ISA slot. Not sure if any recent OS supports it. Microsoft called theirs "Inport" or something like that.

edit: sorry, just dug one out, bus mouse used a 9 pin mini-DIN, not 8.

[jorgenslee]

Yeah, though I'm not familiar with the symbol. Kindly see below.

It's just manufacturer's logo: stylized "CH" letters.

Thanks for pointing that now. Just realized it now. lol

I've never seen PS/2 or ADB devices with non-standard connectors. AFAIK MiniDIN-4 and MiniDIN-6 were integral part of these standards.

As for yours, it looks to me like CD-i pointing device connector (kind of serial):

Base on the Mini Din8a diagram you posted. I checked and only pin 2 = orange, 3 = white, and 4 = blue, shell = black has connections. It does not matched any of the one on diagram.

I'm not familiar with that specific trackball, but if it's from the '80s or early '90s I would guess it uses bus mouse protocol. Logitech, Microsoft, and others used that interface for a while, and it did work through an 8 pin mini-DIN. The associated PC card plugged into an 8 bit ISA slot. Not sure if any recent OS supports it. Microsoft called theirs "Inport" or something like that.

edit: sorry, just dug one out, bus mouse used a 9 pin mini-DIN, not 8.

Yeah, I was actually hoping it is the busmouse after I realize it's not ps2 since we already have a resource here by courtesy of GuilleAcoustic:viewtopic.php?t=9874

[Findecanor]

edit: sorry, just dug one out, bus mouse used a 9 pin mini-DIN, not 8.

Microsoft's "Inport" standard did. "Bus mouse" is not a protocol but when you have everything inside the mouse wired directly in parallel on a "bus" to the host (or other upstream device). Several different connectors were used even on PCs by different manufacturers before Inport became the de-facto standard for PC bus mouse.
There must be at least Vcc, Ground, two wires/pins per axis and then one wire/pin per button, i.e. at least 7 wires for a one-button mouse. Because this trackball only has four wires in the cable, it can't be a bus mouse.

BTW, the NeXT's mouse with 8-pin mini-DIN plug was a bus mouse, with 8 wires in the cable.

[Archie]

It does not matched any of the one on diagram.

Well, then you'll need to search further. Joystick Technologies / CH Products has made trackballs with almost any interfaces ever existed - including quite rare and proprietary ones. For example, mine arrived with giant DB-37 connector:




But in fact, I see no much need to find its original connection type: whatever it was, it's not usable now anyway - so you'll have to replace its MCU with something modern.

By the way, what does "MVP" mean? On your trackball it seems like abbreviation of company name: do you have any information about it? The reason I'm asking is, I have "Curtis MVP Mouse" trackball - but never was able to find meaning of MVP letters...

https://forum.trackballs.eu/viewtopic.php?f=17&t=15

[jorgenslee]

By the way, what does "MVP" mean? On your trackball it seems like abbreviation of company name: do you have any information about it? The reason I'm asking is, I have "Curtis MVP Mouse" trackball - but never was able to find meaning of MVP letters...

https://forum.trackballs.eu/viewtopic.php?f=17&t=15

I also don't know that MVP means as I only bought it without a box on ebay.

Well, then you'll need to search further. Joystick Technologies / CH Products has made trackballs with almost any interfaces ever existed - including quite rare and proprietary ones. For example, mine arrived with giant DB-37 connector:




But in fact, I see no much need to find its original connection type: whatever it was, it's not usable now anyway - so you'll have to replace its MCU with something modern.
https://forum.trackballs.eu/viewtopic.php?f=17&t=15

Did you convert it from DB-37 connector to USB? Do you have more information how did the process go? Did you use Teensy or Pro Micro to convert it?

[Archie]

Yes, at the end of article I've posted is a link to another one, specifically about conversion:
https://forum.trackballs.eu/viewtopic.php?f=16&t=18

DT225 was converted by very similar technique, but I haven't finished the article about it yet.

[Findecanor]

BTW, both old Macintosh and Silicon Graphics used 8-bit mini-DIN for serial ports, although I find that unlikely...

[Archie]

Very unlikely indeed. Never owned SGI, but on old Apple machines serial pointing devices were not normally supported, at least by MacOS itself. That doesn't mean it can't be done, though: during my Mac-addiction period, it was impossible to find ADB trackball in my country - so being a baller, I've managed to connect PC-style serial trackball to my Performa-400 and Quadra-950. It was done by making DIY adapter cable to convert from RS-232 DB-9 to differential RS-422 MiniDIN-8, and installing third-party driver (well, Control Panel, of course)...

But you've given me a valuable clue by mention of these old workstations! Many years ago, I've used to have Sun SPARCstation machine with MouseSystems optical mouse - and now I've recalled it used MiniDIN-8 as well. Checked the pinout:




Seems to be a perfect match to the pins 2, 3 and 4 reported by jorgenslee for his trackball...

[jorgenslee]

Very unlikely indeed. Never owned SGI, but on old Apple machines serial pointing devices were not normally supported, at least by MacOS itself. That doesn't mean it can't be done, though: during my Mac-addiction period, it was impossible to find ADB trackball in my country - so being a baller, I've managed to connect PC-style serial trackball to my Performa-400 and Quadra-950. It was done by making DIY adapter cable to convert from RS-232 DB-9 to differential RS-422 MiniDIN-8, and installing third-party driver (well, Control Panel, of course)...

But you've given me a valuable clue by mention of these old workstations! Many years ago, I've used to have Sun SPARCstation machine with MouseSystems optical mouse - and now I've recalled it used MiniDIN-8 as well. Checked the pinout:




Seems to be a perfect match to the pins 2, 3 and 4 reported by jorgenslee for his trackball...

Looks like a perfect match indeed as I discovered last week that the black wire that is connected to the shell has no circuit trace on the pcb aside from the connector socket. Pin 2 looks like the ground as it is connected most to the components on the pcb. With pin 4 as mouse receive only, is there a adapter that converts this directly without having to remove the controller inside the trackball?

Thanks for the input guys. I'm glad there are still ballers out there. I'm a fan of DT225 as it's form factor suits my use case. Hopefully I can get this working soon.

[Archie]

I doubt you'll be able to find a converter: Sun always was a "niche market", and prior to your CH it was only ITAC known to me who made compatible trackballs...

I'm pretty sure your best bet is to replace the controller. Not a big deal BTW, and if you don't want to deal with Arduino and similar things - you can just buy old PS/2 ball mouse and cheap USB converter, to transplant the controller into your DT225.

[jorgenslee]

I doubt you'll be able to find a converter: Sun always was a "niche market", and prior to your CH it was only ITAC known to me who made compatible trackballs...

I'm pretty sure your best bet is to replace the controller. Not a big deal BTW, and if you don't want to deal with Arduino and similar things - you can just buy old PS/2 ball mouse and cheap USB converter, ant transplant the controller into your DT225.

Thanks, I'll try your approach of replacing the controller if it's within my reach of capability.

you can just buy old PS/2 ball mouse and cheap USB converter, ant transplant the controller into your DT225.

Sorry not sure if I get this. Do you mean to say I get a regular ps2 trackball mouse or a regular ball mouse where the bottom is a ball? It's a first I heard of using this approach, do you have a link to an article I can read and review. I'm curious if this is a viable approach in my situation.

[Archie]

Regular plain vanilla ball mouse. Dirt-cheap or free nowadays. It uses the same quadrature detectors and slotted shutter discs as your trackball: you'll just need to re-wire things.

P.S. Avoid Logitech mice, as many of them use proprietary detectors, not discrete quadrature ones.

[Archie]

Meanwhile, out of curiosity I've finally discovered who is that MVP your trackball was OEMed for:

[jorgenslee]

Meanwhile, out of curiosity I've finally discovered who is that MVP your trackball was OEMed for:

Good to know. Now I'm curious what machine my trackball has been connected to.

Meanwhile I haven't got the time to make it working, though I currently use the case and the bearing as I have other CH DT225 that has a broken case and a stuck bearing. I'll keep an eye on your forum in case you decided to publish your CH DT225 mod.

[Archie]

Will do that later. By the way, you're welcome to register there.

As for stuck bearings - don't discard them! They're of fine quality, and relatively easy to restore with some patience and basic tools:
https://forum.trackballs.eu/viewtopic.php?f=18&t=12

[jorgenslee]

Will do that later. By the way, you're welcome to register there.

As for stuck bearings - don't discard them! They're of fine quality, and relatively easy to restore with some patience and basic tools:
https://forum.trackballs.eu/viewtopic.php?f=18&t=12

Done registering.

Will check that out. Thanks

[keyboardist]

Attaching detailed info on a trackball I found a documentation from producer - it can be switched to few different protocols actually and have few DPI options to choose.

New CH DT 255 costs almost 2 times more than new CST - L-trac trackballs. At least when you don't buy them in bulk.
Here is the only shop I found listing prices.
https://mt.rsdelivers.com/product/ch-pr ... ll/7651150
https://mt.rsdelivers.com/product/ch-pr ... ll/4646082

[Archie]

Attaching detailed info on a trackball I found a documentation from producer - it can be switched to few different protocols actually

So, exactly how do you switch the protocols on DT225?

[keyboardist]

Some time ago it was adjusted by setting DIP switches.

[bebop8]

Attaching detailed info on a trackball I found a documentation from producer - it can be switched to few different protocols actually and have few DPI options to choose.

New CH DT 255 costs almost 2 times more than new CST - L-trac trackballs. At least when you don't buy them in bulk.
Here is the only shop I found listing prices.
https://mt.rsdelivers.com/product/ch-pr ... ll/7651150
https://mt.rsdelivers.com/product/ch-pr ... ll/4646082

That naming convention sheet is very interesting. It lists 3 different DPI model configurations on the DT225; so does that mean CH Products offered 3 different sensor variants? Also I see that reseller is listing 2 different models, x20 and x30 with (I guess) different resolution levels, priced accordingly, which seems to corroborate that.

Been looking for a DT225 locally. Now of course I want the high DPI variant if at all possible . I wonder how one can tell what sensor a DT225 has without the model number.

[Archie]

My understanding is, these resolution codes just reflect shipped state of DIP switches. Native sensor resolution on my DT225 is 360 PPR with capability to divide or multiply it by 2 with DIP setting, and I have never seen pictures of other variants with shutter discs visually different from mine...

[bebop8]

My understanding is, these resolution codes just reflect shipped state of DIP switches. Native sensor resolution on my DT225 is 360 PPR with capability to divide or multiply it by 2 with DIP setting, and I have never seen pictures of other variants with shutter discs visually different from mine...

Thank you for clarifying. If I could ask, have you tried it with the dip switches configured for the highest sensor resolution? If so, how was it?

I ask because my Itac throws accuracy out the window in high speed mode. Looking for a trackball that's just as robust and with ball bearings but with higher DPI/PPR than the Itac's ~200 (even with accel at 10 in Linux, I could use more DPI on the desktop).

[Archie]

Having both, I'd say CH is much more usable than ITAC on modern systems. Of course I keep it in doubled resolution mode, but even native one outperforms ITAC's 192 PPR.

Mechanically they're nearly identical: exactly the same type of bearings & shaft diameter, but CH have slightly bigger ball and better arrangement of buttons. No integral wrist rest, though.

If you need high-resolution trackball with ball bearings, maybe it's worth to try semi-DIY derivative of defunct Microsoft Explorer trackball, as all the factory-made units still in production today are AFAIK low-resolution (by modern standards) devices.