IBM Model M 1989 Ger

[alp3n]

Hello

Im new here I'am owner of this keyboard. I want to know what kind of plug is it?
Mby you know? Help me please.
Some photos:
http://imgur.com/a/drbQd

If I turn it on I will Mod it later.

Greetings

[CPTBadAss]

I *think* that's a DIN5 connector. You can get a DIN5 to PS/2 adapter. And then if you want, you can get a PS/2 to USB adapter as well.

[Aer Fixus]

It appears to just be PS2. It's missing pins, but PS2 keyboards don't use them all anyway, so some of the cables have missing pins. From what I have heard, early (non-terminal) Model M keyboards had XT and AT connectors, but never DIN 5***. Also, given that this keyboard was made in 1989 and has the indicator lights, this is almost certainly PS2 (please correct me if I am wrong).

If it is PS2, you can just plug it into the back of your motherboard or, if your motherboard does not have a port for it or it is not compatible for some reason, you can get the "blue cube," a PS2 to USB converter that is known to work well with Model M keyboards.

***Correction: AT and XT are DIN 5 connectors. A simple mis-remembering of information.

Knowing this, this is not DIN 5/AT/XT and is definitely PS2.

[alp3n]

Yeah thats what I thought.

http://imgur.com/TO8gd9g

There should be 2 more pins but there is no place for them only 2 round shades. It's a defect in production or first plugs was like this one?

[Aer Fixus]

Many keyboard/mouse plugs are like this, not just certain Model M's. I'm not sure which models do this specifically, but including gold plated pins that are unused is a waste of resources, so I imagine that they cut them out to save some costs. It is not a defect, nor does it effect the usability of the keyboard in any way, shape or form.

[alp3n]

Now i need to find somewhere in house PS/2 to USB ;p and see if it works

Thank you very much

[Aer Fixus]

A quick note regarding the PS2 to USB converter. You may find that some converters do not work or even break when used with a Model M. The reason is because the model M pulls a lot of current and most converters do not provide it. This is the converter that most M users swear by: http://www.amazon.com/PS2-Keyboard-To-USB-Adapter/dp/B000BSJFJS

Note: other converters MAY work, but they are not guaranteed to work with your M (and don't be surprised if you plug it in and the keyboard doesn't respond. The keyboard is most likely not broken. It takes a lot to kill one of these keyboards!). Also, you do not have to purchase it from Amazon. That link is just for reference so you know what to look for.

[alp3n]

Ok thanks !

[bazemk1979]

that poor thing needs a bath...

[rootwyrm]

That's a 1989 PS/2 "reduced cost" cable. It will not work with many USB to PS/2 adapters. Other than the missing pins, the keyboard is just another Model M. They're somewhat uncommon but completely interchangeable with any other M cable.

Pins used are 5, 4, 3, and 1. That's Clock, Vcc, Ground, DATA+. The problem with the cost reduced cable and adapters is that many of them are poorly designed and dependent on the resistance change from the non-connected pins (6 and 2) to work properly. IIRC, the BlueCube suffers from this problem - which is why I still prefer the Belkins. Why this is, I have no idea. It will however, work just fine with every PS/2 port out there as long as it can supply 225mA.

[Aer Fixus]

I didn't know that the missing pins effected its compatibility with certain converters...

Good to know.

[mich]

Pins used are 5, 4, 3, and 1. That's Clock, Vcc, Ground, DATA+. The problem with the cost reduced cable and adapters is that many of them are poorly designed and dependent on the resistance change from the non-connected pins (6 and 2) to work properly.

??

Is this some speculation or have you really observed a keyboard and adapter which only worked with 6-pin cables, disassembled the adapter and found out ... what exactly? What resistance are they sensing, where and how?

FWIW, I have two crap adapters and none of them even connects these pins to anything. And none should, IMHO

[rootwyrm]

Pins used are 5, 4, 3, and 1. That's Clock, Vcc, Ground, DATA+. The problem with the cost reduced cable and adapters is that many of them are poorly designed and dependent on the resistance change from the non-connected pins (6 and 2) to work properly.

??

Is this some speculation or have you really observed a keyboard and adapter which only worked with 6-pin cables, disassembled the adapter and found out ... what exactly? What resistance are they sensing, where and how?

FWIW, I have two crap adapters and none of them even connects these pins to anything. And none should, IMHO

If I'm speculating, I say I'm speculating. I can speculate as to the reasons why, but not very elaborately, as I'm not an EE. What I do know is that I've run into this problem - especially on certain Y-cables - and the only explanation is the missing pins. Remember that "NC" does not mean you are not allowed to use the connection. It means there is no standard connection. NC and DNC (Do Not Connect) are totally different. There is absolutely no reason to not dead-end them, and FYI? Those "extra" pins are actually specified as mouse data, which is why they're NC not DNC.
 
There are several folks who have found similar oddities with regards to resistance affecting IC operation on USB adapters, typically RS-232 serial adapters. Same would seem to be the case in PS/2-USB adapters. A lot of keyboards connect the extra pins to go-nowhere vias or pads or the ground plane. Which no surprise, affects the overall resistance and current and something about signals. (I don't know the details, I'm not an EE!)

[mich]

It's hard to tell anything without knowing the exact setup you used for testing, but I don't think it had anything  to do with NC pins. Adapters can't assume that these pins exist and are connected to anything because modern keyboards (and many Ms and M2s, too) dead-end them immediately in the PS/2 plug to reduce cable cost and thickness. Ms shouldn't assume anything like this either because IBM sold 4-pin cables and because their AT and PS/2 host controllers probably dead-end these pins in the socket (except for laptops adapted for Y-splitters). Also, I'm not even sure if these SDL cables with 6-pin plugs really have 6 conductors inside and not only 4 (not counting the extra chassis ground wire).

[alp3n]

I cleaned it up and it works!
Yeah Thank you all!
I got this conventer http://tnij.org/ps2port

[rootwyrm]

It's hard to tell anything without knowing the exact setup you used for testing, but I don't think it had anything  to do with NC pins. Adapters can't assume that these pins exist and are connected to anything because modern keyboards (and many Ms and M2s, too) dead-end them immediately in the PS/2 plug to reduce cable cost and thickness. Ms shouldn't assume anything like this either because IBM sold 4-pin cables and because their AT and PS/2 host controllers probably dead-end these pins in the socket (except for laptops adapted for Y-splitters). Also, I'm not even sure if these SDL cables with 6-pin plugs really have 6 conductors inside and not only 4 (not counting the extra chassis ground wire).

mich, I've been working with these things for years. While it's hard to say for absolute certain what the issue is without an EE present, that's the issue. I have owned M's from new, so yes, I do know them quite well thank you. And as the saying goes, attribute not to malice that which is sufficiently explained by incompetence. They're not supposed to assume an NC pin is present - that doesn't mean they don't anyways because everybody else puts them in. I have had all KINDS of fun with that in serial land.
Also, the host implementation NEVER dead-ends those pins. It is not permissible under the spec. Those pins must be connected at all times. There is not a single PS/2-compliant host port out there which will not take an inverse Y cable (PS/2 host to kbd+mouse) because of it. That's why many motherboards with a PS/2 port these days have a bi-color (green+purple) single port. You use a Y-cable and it uses the full 6 pins, per spec. And yes, most implementations do violate spec and have for years. But since it's hard as hell to test and it wasn't a big deal except on laptops way back when, well, nobody cares.

As to the SDL 6-pins - it varies. Most are either plug dead-end terminated to shell or terminated to drain wire. There's an extremely rare cable which is SDL to PS/2 with all six connected, using the mouse data lines per spec. (No Y-cable required, in other words.) I've only seen photos though - the Y cable was just easier because we're talking about pre-ATX. ATX 1.0 wasn't official until 1995 and until about '97-'98ish you could still get BabyAT. Which meant DIN5 (AT) plus a PS/2 mouse bracket. My first M13 was on an MSI-5184 with DIN5+PS/2.

I cleaned it up and it works!
Yeah Thank you all!
I got this conventer http://tnij.org/ps2port

Yep, that's the same as the Belkin. It's a remarkably good adapter all in all. I've had no complaints save with certain SMK's. (I'm STILL debugging why that is. They don't work right with ANYTHING.)

Happy typing.

[Soarer]

I wish I hadn't noticed this thread - now I feel compelled to correct / clarify the 'information' given by rootwyrm above.

The 'spec' is the PS/2 Hardware Interface Technical Reference Manual, May 1988. Section 10 page 15 details the PS/2 keyboard (and the identical auxiliary device, aka mouse) connector pinout as having 2 connections marked as 'reserved'. Section 14 page 50 details the SDL to PS/2 cable as having 6 wires connected, again with 2 connections marked as 'reserved'. (The RS/6000 keyboard uses the same cable, and uses those connections for its speaker).

Reserved... to be truly compatible, neither host nor device should make any connection to those pins.

Indeed that's what we find - as long as a keyboard makes no connection to those pins, it should work on any 'PS/2 compatible' host or adapter. As long as a host or adapter makes no connection to those pins, it should work with any 'PS/2 compatible' keyboard. Other errors may prevent some combinations of host and keyboard from working, but it's not that either end expects any particular connection or resistance on those pins, as long as they conform to the spec.

The blue cube, BTW, makes no connection at all to the reserved pins. Plus, it's known to work with Model Ms.

A dual-port (keyboard + mouse) PS/2 connector on a host does not conform to the PS/2 spec. (it has its own spec), but, when the Y-cable is used, the two ports it provides do conform - no connection is made to the two reserved pins on either keyboard or mouse connector. As a bonus, if a conformant keyboard is connected directly to the dual-port socket there is absolutely no difference compared to using the Y-cable.

In fact, as long as either the host or the keyboard conforms and does not connect the reserved pins, there is no problem. If non-conformance is limited to tying one or both reserved pins to ground, there's also no problem even if both host and keyboard do it. Statistically, I have no idea how many keyboards do not conform, but since most use 4 wire cables, I'd say it's likely that most conform! Anyway, given that only one end has to conform, it's quite feasible that many hosts and/or keyboards do not strictly conform. However, a host (or keyboard) that depends on having a non-conformant keyboard (or host) attached is not going to be broadly compatible - I'd wager that doing that would be specifically to ensure incompatibility.

[microsoft windows]

That's a PS/2 plug. Just put it in your PS/2 port and you're good to go! Or if you need USB, you can just get a PS/2 to USB adapter for a couple bucks.

[ch_123]

EDIT: Soarer already mentioned what I was pointing out (The extra pins were used by the RS/6K speaker)

[rootwyrm]

I wish I hadn't noticed this thread - now I feel compelled to correct / clarify the 'information' given by rootwyrm above.

WTF. Chip on your shoulder much there, dude? You just said exactly what I said. IBM and others used it 'unofficially' for a LONG time. What, you think IBM didn't think of these things in '87, '88? They put the damn mouse pins where they did for a reason. It was formalized as part of the ATX PC'97 specification to make things easier for stacked port arrangement - the reason being all pins on both ports terminate same location with no pin overlap.
Not surprisingly, this is cheaper and easier than playing games where you have to terminate 12 pins in 6 different locations. Which is why there are a LOT of stacked ports from that era that have only 6 or 8 pins connected to the motherboard excluding mount tabs. Nevermind that it started with AT era on some boards. Bracket "PS/2 Mouse" headers would be 8 or 5 pins and share traces with the DIN5; half the time the 8 pin headers were set up for Y-cables, just omitting the KBD_DATA wire.
The whole thing started long, long ago when manufacturers got away from true i8042 and moved to the SuperIO layout. The PS/2 technical reference hasn't been valid or relevant except for signalling and scan codes since ATX 0.9.

Also, ch_123, you are very, very wrong. Absolutely and unequivocally wrong. The RS/6000 setup was a kludge to use off the shelf parts and does not conform in any fashion to any specification but the RS/6000. J10 directly connects to SDL pin 6 only for voltage - pin 2 of J10 goes to common ground plane. They cannot be omitted even if not connected to a speaker - they must have the correct resistance level. Otherwise, the terminal will give a missing pin error and tell you to sod off. Cherry made a G83 that was RS/6000 compatible without a speaker - and it was absolutely terrible.
But anything past a early RS/6000 does not need the keyboard speaker and does not rely on it. Hasn't required it for many, many years. Anything PowerPC 601, 603, 604e (incl. X5) or later is straight up PS/2 host side. But please, do tell me I wasn't using an M13 on my 7024-E30 workstation with IBM's blessing. Or that feature code 6010 on the 7009-C20 isn't a standard Enhanced 101 and the Enhanced w/Speaker wasn't moved to 6600.

But hey, it's not like IBM didn't do exactly what I'm describing on the IBM ThinkPad 860 AKA RS/6000 Laptop and the predecessor 851.

[Soarer]

EDIT: Soarer already mentioned what I was pointing out (The extra pins were used by the RS/6K speaker)

Yes   I was going to say a bit more about it, but decided not to pollute that post... I saw the RS/6000 pinout next to the PS/2 pinout here.

I have an LED-less Model M which grounds pin A of the SDL - the same position as 'speaker ground' on the RS/6000. So if a 6-wire SDL cable is used it, will ground pin 6 of the PS/2.

I also have an early 1390136 (square label) M, and it does not ground that pin.

Neither of them ground the other reserved pin.

Unfortunately, I've mixed up the two cables One was a 4-pin and one was a 6-pin. Hopefully I've got a picture archived that will tell me which keyboard had which cable...

[Soarer]

I wish I hadn't noticed this thread - now I feel compelled to correct / clarify the 'information' given by rootwyrm above.

WTF. Chip on your shoulder much there, dude? You just said exactly what I said.

I did not.

Just to distil it down to one key point...

Also, the host implementation NEVER dead-ends those pins. It is not permissible under the spec. Those pins must be connected at all times.

... neither host nor device should make any connection to those pins.

... more like the polar opposite!

The PS/2 Tech Ref is still totally valid, since anything coming after attempts to be compatible with it. Dual-port PS/2 adds a function to those reserved pins which could/should be completely compatible (but is not conformant).

[Soarer]

But hey, it's not like IBM didn't do exactly what I'm describing on the IBM ThinkPad 860 AKA RS/6000 Laptop and the predecessor 851.

Interesting...

Keyboard/Mouse Y connector is required to attach the external keyboard to the system.

Required for keyboard, but not for mouse. Makes sense for a laptop. But it means they didn't trust querying the ID to find out what was attached to each PS/2 interface!

Are Y-cables all the same - as in having mouse on the normal pins and keyboard on the reserved pins?

What does the ATX PC97 spec say, exactly?

All I can find is a line in the PC99 spec (p214) which says that the mouse port must:

Comply in full with requirements in the Personal Sysem/2 Specification, by IBM

(PC98 says the same).

As far as I can tell, the various PCnn specs don't specify any changes to the PS/2 port specs, which is as one would expect - they are legacy, either implement them or not, but if you do then comply with the old IBM specs.

[mich]

Hell, this topic reminded me of something.

I had a key shortcut which sometimes didn't work and I traced the problem to some software configuration. I changed an option, rebooted and the key worked. Switched it back, rebooted and it didn't work. I repeated this cycle several times to be sure. I became sure.

Whenever I was booting with "good" settings, I hit the key hard to get the expected result ASAP. When booting with "bad" settings, I tended to hit it lightly because I didn't expect it to work anyway. Long story short, after some time I realized that it wasn't software after all

Observations follow expectations. Unfortunately, this is probably the reason behind most "cable quality" stories, not only among audiophiles

[fohat.digs]

What does the spec say, exactly?

"Never butt heads with a butthead."