@bestemor

Does the Cybex work as a stand-alone ps/2-to-serial converter if you don't have the VGA port hooked up and you use a seperate KVM w/audio as the switching KVM (you will have 2 KVM's in series)? The drawback of using the Cybex as the KVM is that it doesn't have the audio port switch. For my interests, not having an audio port switch on a KVM is a complete show stopper. Also, will the Cybex default to port A without any user input if the power is switched off then on? If so, I wonder if we can remove all the unnecessary components in the KVM box and repackage the essential real-estate in a smaller platform?

I have a Belkin Omni View SE F1D102 KVM which I tried to do this same thing on, but it didn't work out as I had hoped.

memsys wrote:

would it not be more useful to make a USB to serial converter? (if that is possible)

I don't think so. Don't most USB mice work on a PS/2 port with a PS/2-to-USB pin adapter? I have found the success rate of going from a PS/2 port to USB mouse much better than going from a USB port to a PS/2 mouse. With a PS/2-to-Serial adapter, you'd be able to use PS/2 and USB mice with greater success.

feipoa wrote:

@bestemor
Does the Cybex work as a stand-alone ps/2-to-serial converter if you don't have the VGA port hooked up and you use a seperate KVM w/audio as the switching KVM (you will have 2 KVM's in series)?

I did not use VGA at all* in my tests, so I think the series options should work - the Cybex KVM will then act as a visual 'bump' on the PS2 cables from the 'master' KVMs mouse (and keyboard**) portside to the serially afflicted PC. But have not actually tested such a setup.

(*: of course had a monitor attached to the PC, heh... but not via KVM)

(**: PS2 from PC is needed for the Cybex to actually work/transferring mouse signals serially - AC adapter no help even if it actually powers up the optical mouse! But... if you wanted, you could use a PS2 splitter at the serial PC - with AT adapter, and still route a PS2 directly to the 'master'/audio KVM, as long as the Cybex got power to the port on a separate cable, I think....? )

Check the review link on anandtech, it says that the Cybex can be daisy-chained to control 64 units(!). Providing your 'master' KVM also has such/similar functionality, then I don't see any problems with what you are proposing.

feipoa wrote:

Also, will the Cybex default to port A without any user input if the power is switched off then on? If so, I wonder if we can remove all the unnecessary components in the KVM box and repackage the essential real-estate in a smaller platform?

Assume you mean powering on/off the 'serial' PC ?
I have no idea about any defaults, I've only hooked up a single serial cable(and PS2) to 1 computer. Using port 'D' for the cabling. Which it 'defaulted' to every time 🤣 .

Hence if only one PC connected, I think the Cybex defaults to the port(A-D) where the PS2 cable is attached.
And, for chopping into bits, perhaps the smaller(assuming at least the inner pcb is smaller) 2-port model would be a better target ?

PS2 from PC is needed for the Cybex to actually work/transferring mouse signals serially

I don't understand this statement. You have the PS/2 mouse hooked into the far left-end of the back of the KVM. Then you have a serial mouse connected to port D. At which point do you have a PS/2 from the PC connected to the Cybex?

Are you are able to leave the keyboard unconnected to the KVM for the mouse conversion to work?

Sorry for late reply, but been hit hard with seasonal virus and could barely muster the will to stand up... still recovering.... 😵

I'll try to explain better.

You have the PS/2 mouse hooked into the far left-end of the back of the KVM.

Correct. ("User Console" ports)

Then you have a serial mouse connected to port D.

INcorrect. No mouse, but a serial extension cable, male-female, which other end is into serial port on PC.

At which point do you have a PS/2 from the PC connected to the Cybex?

From the PC's AT-port via passive adapter, to the keyboard PS2 connector on the same(!) letter port as the serial extension cable.

Are you are able to leave the keyboard unconnected to the KVM for the mouse conversion to work?

Due to lack of a Y-splitter(PS2), I am not able to actually test it, but I see no reason why not. Tested without keyboard, and the KVM lights up, which to me is a strong indication that it actually is 'on' and ready to send signals. Without PS2'power' from PC it looks just dead, no-matter if my AC adapter works just fine and powers the mouse(via the Cybex).

EDIT: having a DOS/win311 hdd connected to mobo, I started up WITH keyboard connected to the Cybex (to be able to type 'win' + Enter), then disconnected the keyboard. Mouse still works as before - hence a PS2-splitter should be fine, unless that in itself would cause any problems vs keyboard functionality (?).

- Minimum hardware needed for a non-daisy-chained KVM set-up and with a separate mouse and direct connect keyboard is:

(1) - Cybex KVM, of course
(2) - serial male-female extension cable
(3) - PS2 male-male cable
(4) - an AT-to-PS2 passive adapter
(5) - PS2-splitter adapter (not tested, do not own currently)
(6) - the serial offender...(PC) 🤣
(7) - PS2 or USB(via passive PS2 adapter) mouse.

Setup:
Plug in your (4) to the keyboard port on (6).
Connect (5) to (4).
Connect male end of (2) to any 'letter' port on (1).
Connect (3) to (1), using the keyboard port with same letter as (2) is connected to, the other end of (3) to (5).
Connect (a PS2 cable from your KVM of choice, OR just) a keyboard directly, to the remaining receptor on (5), and then VGA cable and sound etc as you normally would.

Finally - plug your (7) into the "User Console" PS2 mouse port.

Untested: instead of the last step above, plug your regular KVM PS2 (mouse port) cable-to-PC in at the same spot. Hopefully this should enable use of a mouse via normal (second) KVM.

Minimum connections needed are shown below.
Optionally it SHOULD also work if daisy-chaining both PS2 "User console" ports to a second KVM.
Making it possible to control all parts via that second KVM, but VGA(if you prefer) and sound via separate cables DIRECTLY from second KVM to PC.

So it sounds like this KVM cannot be used as a PS/2-to-serial mouse converter without the keyboard hooked up, however there should not be any issue to connect multiple KVM's in series. You could think of the KVM as a 6" extnesion cord for the keyboard. However, what if you just add VCC and GND to the keyboard input port? Would that be sufficient to not need the keyboard connected?

So it sounds like this KVM cannot be used as a PS/2-to-serial mouse converter without the keyboard hooked up,...

I have to respectfully disagree - look below, NO keyboard to Cybex! 😁
This is just a visualization of the setup in my previous post...

But, I am of course assuming you use a PS2 keyboard - if AT, then it would still be possible, but a bit harder to find a splitter (I found 'one' though!).

However, what if you just add VCC and GND to the keyboard input port? Would that be sufficient to not need the keyboard connected?

Hmm, no idea (translating 'keyboard' as PS2 cable, and 'input port' = located on port-D ).
I suspect there is some sort of logic in the Cybex that checks for 'something'*, and that MAY be for a 'power signal' into the appropriate PS2 letter port. So hey, who knows.... 😁
*: I mean, there must be a reason for it NOT working with 'only' an AC adapter, so maybe just power is not enough but also something on those other pins ?

I still think my VERY simple circumvention with the Y-adapter is mucho easier though, heh... 🤣
Granted, you still need to feed the Cybex with a live PS2 cable, but this way it at least does not block the keyboard from actually being connected to the PC.

And, just tested, connected the PS2 cable from Cybex port-D to a totally unrelated ATX PC(not turned on/but PSU is 'on'), and serial cable from Cybex to the serial PC(as before), and the mouse STILL works, so there.... No keyboard anywhere near that Cybex, L OL

* * *

Of course, KVM series connection as you suggest, should make all this a non-issue.

You could think of the KVM as a 6" extnesion cord for the keyboard.

And mouse as well. Yep, me knows - that what was I meant by 'visual bump' in earlier posting...

Well, all considered I regard this Cybex to be a find vs serial mouse conversion - even with the need for a PS2 cable to be connected.
At least when reading about other peoples less fortunate experiences with Raritan, Vetra and other converters.
(I actually was very close to ordering the expensive Vetra once, now I'm glad I didn't...)

feipoa wrote:

So it sounds like this KVM cannot be used as a PS/2-to-serial mouse converter without the keyboard hooked up...

Let me rephrase that to,

So it sounds like this KVM cannot be used as a PS/2-to-serial mouse converter without the keyboard port of the Cybex hooked up...

That was the original intent of my sentance. Your diagrams both have the keyboard port hooked up to some capacity. In general, your results seem promising. I'm still going to try the route with the PIC circuit though.

Edit:

feipoa wrote:

Then you have a serial mouse connected to port D.

bestemor wrote:

INcorrect. No mouse, but a serial extension cable, male-female, which other end is into serial port on PC.

Sorry, I've been getting too distracted while replying to posts recently. I obviously did not mean to say serial mouse as that would defeat the whole point of this thread.

Usually KVMs use the presence of Vcc on the keyboard socket to determine if a computer is "on", their internals are usually powered from there too.

More advanced ones can use the presence of sync on the monitor port too.

I'm looking forward to the PIC solution also.

What voltage power adapter are you using? I wonder if we could get away with 5 V from the PSU to power this thing instead of the 6 V required.

What voltage power adapter are you using?

6V.

BUT, that adapter was only used when testing without PS2.

For actual use, it is not needed.
The PS2 cable power it gets from the PC is perfectly sufficient.
So, 5V DC @ 275 mA should be just fine.....

bestemor wrote:

For actual use, it is not needed.
The PS2 cable power it gets from the PC is perfectly sufficient.
So, 5V DC @ 275 mA should be just fine.....

Doesn't need to be powered? These are very promising results. I have purchased one of these KVM boxes and will test it along with the PIC circuit solution.

feipoa wrote:

memsys wrote:

would it not be more useful to make a USB to serial converter? (if that is possible)

I don't think so. Don't most USB mice work on a PS/2 port with a PS/2-to-USB pin adapter? I have found the success rate of going from a PS/2 port to USB mouse much better than going from a USB port to a PS/2 mouse. With a PS/2-to-Serial adapter, you'd be able to use PS/2 and USB mice with greater success.

PS/2 is going the way of the Dodo and keyboards and mice that support PS/2 (with or without a passive adapter) are getting harder and harder to find, a lot of new motherboards only have a shared mouse/keyboard PS/2 port.
It probably won't be long until PS/2 is gone.

Yes, USB -> PS/2 -> serial would work better then PS/2 -> USB -> serial.
However when PS/2 is gone you would need a active adapter(USB -> PS/2) for your active adapter (PS/2 -> serial)

Yea just recently ordered two PS/2 keyboard / mouse sets. V7 branded, never heard of them, but one of the few budget products I could find. Works wonderful with my KVM.

memsys wrote:

PS/2 is going the way of the Dodo and keyboards and mice that support PS/2 (with or without a passive adapter) are getting harder and harder to find...

I think pretty much all of this retro hardware we are playing with is going extinct, so the lack of modern PS/2 peripherals isn't really a topic of concern in itself. We are all already searching with much effort for rare motherboards, CPUs, etc. Adding PS/2 to the mix is not going to sway us.

Is there any way to adapt Apple ADB keyboards and mice to PC?

sliderider wrote:

Is there any way to adapt Apple ADB keyboards and mice to PC?

Yes, via USB to ADB adapters.

Adding a real PS/2 mouse port to an AT board seems like a fun challenge. Based on the documentation I could find, PS/2 mouse systems used a dual channel Intel i8042 keyboard controller with the mouse on the 2nd channel and tied into IRQ 12.

Seeing that most keyboard controllers are discreet socketed chips on these old boards, it could be possible to swap them out for the dual channel version. You'd have to run a wire to the IRQ12 line on an ISA slot, and wire up a 2nd PS/2 port. I don't know if any BIOS changes are needed to get a PS/2 mouse to be visible on a system. The lack of any required BIOS hooks could be taken care of with an option ROM to activate the port on boot or even a DOS device driver.

memsys wrote:

Yes, USB -> PS/2 -> serial would work better then PS/2 -> USB -> serial.
However when PS/2 is gone you would need a active adapter(USB -> PS/2) for your active adapter (PS/2 -> serial)

Long term, it's just going to make sense to go from USB->Serial. But then we're outside the realm of what can be easily accomplished with just a PIC. You'd need a USB host microcontroller for that. You're looking at something at least as complex and expensive as an arduino.

NJRoadfan wrote:

Yes, via USB to ADB adapters. […]
Show full quote

sliderider wrote:

Is there any way to adapt Apple ADB keyboards and mice to PC?

Yes, via USB to ADB adapters.

Adding a real PS/2 mouse port to an AT board seems like a fun challenge. Based on the documentation I could find, PS/2 mouse systems used a dual channel Intel i8042 keyboard controller with the mouse on the 2nd channel and tied into IRQ 12.

Seeing that most keyboard controllers are discreet socketed chips on these old boards, it could be possible to swap them out for the dual channel version. You'd have to run a wire to the IRQ12 line on an ISA slot, and wire up a 2nd PS/2 port. I don't know if any BIOS changes are needed to get a PS/2 mouse to be visible on a system. The lack of any required BIOS hooks could be taken care of with an option ROM to activate the port on boot or even a DOS device driver.

Does the Apple keyboard's "power on keypress" feature still work?

Hi there.

After reading this thread I could feel the Vogon Collective's pain about not being able to use a decent mouse on an old computer.

Last week I therefore coded up a working PS/2 to serial mouse converter on a PICMicro.

Here is a quick and dirty demo:
http://youtu.be/_iGMpO0fris

If you are interested in this then I should create a new topic in the forum section where I will link to the assembly source file and an example circuit schematic.

There is further work required for the circuit though, since the demo doesn't have a PSU nor does it attempt to use the RS-232 lines to power itself.

Bye

Did you take the ground-up approach, or did you use the Amiga converter code posted by keropi?

Yes, please include a circuit schematic and source code. Did you write it using a C-compiler for PIC or use assembly from the onset?

How was the mouse tracking quality at 1280x1024 in Windows?

If you are not using RTS and DTR on the serial port, you may be able to use either of these with a voltage regulator power the device, however the output is limited to 10 mA. Put a multi-meter in line to see what the typical current consumption of the PIC is under mouse operation.

You might be able to use RTS and DTR on the serial line to power the PIC, however you will need to set RTS or DTR active by default (to output 10 V). Perhaps this is possible with a simple DOS driver at boot time.

EDIT: According to the PIC16F8X datasheet, the currnet draw is less than 2 mA at 5 V. I think most serial ports shouldn't have a problem with that. I've used serial ports to create 5 V regulated in the past and didn't have any issues.