# Dumb Terminal Keyboards on Gentoo PCs?

## MADcow

i just got my paws on an IBM Model M #1392980. its interface is (i guess) for a dumb terminal - it looks like an ethernet cord. i was wondering if there was some way i could hook this thing up to my AMD/Gentoo machine for everyday use (preferably without buying anything   :Very Happy:  ).

cheers, thanks for the help!

EDIT: looks like rj-45, not rj-11 (phone)Last edited by MADcow on Tue May 30, 2006 12:19 am; edited 1 time in total

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## troymc

 *MADcow wrote:*   

> i just got my paws on an IBM Model M #1392980. its interface is (i guess) for a dumb terminal - it looks like a phone cord. i was wondering if there was some way i could hook this thing up to my AMD/Gentoo machine for everyday use (preferably without buying anything   ).
> 
> cheers, thanks for the help!

 

Actually, I think you just gave us the info for the keyboard. If nothing else you have yourself one of the finest keyboards ever made. People start holy wars over the old Model M keyboards.

As for your dumb terminal, most likely that is some sort of serial connection. But whether it is RS232 or not, we won't know until you can more fully identify what you have.

troymc

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## MADcow

the connector on the end of the keyboard cord looks exactly like an RJ-45 jack... male...

EDIT: i meant for the keyboard. the dumb terminal part was me assuming the keyboard came from an ancient terminal and that's why it had a weird connection. just a guess. maybe it's some kind of "swappable" keyboard cord from IBM?

so, to clarify, i have no Dumb Terminal, i have a keyboard that might have come from one. i want to hook this keyboard to my desktop, because it's a bitchin' keyboard.

cheers!

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## troymc

 *MADcow wrote:*   

> the connector on the end of the keyboard cord looks exactly like an RJ-45 jack... male...
> 
> EDIT: i meant for the keyboard. the dumb terminal part was me assuming the keyboard came from an ancient terminal and that's why it had a weird connection. just a guess. maybe it's some kind of "swappable" keyboard cord from IBM?

 

Ah, I understand now.

You are probably correct. It's probably just a special cord put on for their dumb terminals.  I wonder if you could cut that off & wire on a standard AT keyboard connector?

How many wires are in the connector? If I remember correctly the old AT keyboards used 5 pin DIN connectors.

troymc

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## MADcow

my eyes aren't very good, but i think i see five wires inside of the 7-pin rj-45-like housing

so, five wires hooked up to the pins, even though there's seven pins - 2 pins aren't being used at all.

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## troymc

 *MADcow wrote:*   

> my eyes aren't very good, but i think i see five wires inside of the 7-pin rj-45-like housing
> 
> so, five wires hooked up to the pins, even though there's seven pins - 2 pins aren't being used at all.

 

Sounds good!  Got the iron hot & tinned?

Probably need a AT to PS2 keyboard adapter, and maybe a PS2 to USB.

troymc

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## MADcow

so, if it's 5 pins, it's likely DIN - right?

but since one of DIN's pins isn't used, and two of PS/2's pins aren't used, can i wire it up to an old PS/2 connector and have it work?

according to this URL, they use the same voltage.

http://www.electronic-engineering.ch/microchip/datasheets/pinout/pinout.html#keyboard_5

so, are the CLOCK and DATA protocols the same on PS/2 and DIN? and if so, which wires in the RJ-45-like-cable would correspond to which?

and how risky is it to mess with this? might i fry my PS/2 controller?

cheers!

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## troymc

 *MADcow wrote:*   

> so, if it's 5 pins, it's likely DIN - right?
> 
> but since one of DIN's pins isn't used, and two of PS/2's pins aren't used, can i wire it up to an old PS/2 connector and have it work?
> 
> 

 

Yes! The PS2 & AT connectors were electrically identical, they just used different plugs.

 *MADcow wrote:*   

> 
> 
> so, are the CLOCK and DATA protocols the same on PS/2 and DIN? and if so, which wires in the RJ-45-like-cable would correspond to which?
> 
> and how risky is it to mess with this? might i fry my PS/2 controller?
> ...

 

Hmm...maybe go by color code?

troymc

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## MADcow

ok, i opened up an old PS/2 cable - i've got Red, yellow, black, white.

inside my Model M RJ-45 connector, i've got Red, yellow, white, black, and black.

i'll assume that it's more design than coincidence, so i'll guess that one of the blacks in the Model M cord is nothing.

i wonder which.

anyway, here's what i plan - i'm going to dig up a female RJ-45 connector and plug the Model-m into it. then i'll wire my ps/2 cable into the female rj-45 box. that way i won't mess up the Model M's cable. any suggestions on how to do this without soldering? i suck at soldering and i'm out of solder...

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## troymc

 *MADcow wrote:*   

> ok, i opened up an old PS/2 cable - i've got Red, yellow, black, white.
> 
> inside my Model M RJ-45 connector, i've got Red, yellow, white, black, and black.
> 
> i'll assume that it's more design than coincidence, so i'll guess that one of the blacks in the Model M cord is nothing.
> ...

 

I got $20 says they're the same and they're ground!

 *MADcow wrote:*   

> 
> 
> anyway, here's what i plan - i'm going to dig up a female RJ-45 connector and plug the Model-m into it. then i'll wire my ps/2 cable into the female rj-45 box. that way i won't mess up the Model M's cable. any suggestions on how to do this without soldering? i suck at soldering and i'm out of solder...

 

Hmm....maybe dig up an old PS2 device and sacrifice its connector? Cut off about a foot.  Wire nuts & electrical tape?  or just electrical tape?  I've used duct tape in a pinch, but some of it is conductive!   :Shocked: 

troymc

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## MADcow

yeah, i've already sacrificed the connector, but i don't want something that will damage the model m's cord, so i need to grab a female rj-45 while i'm in town tomorrow. i think i'll go for one of those wall plates, since it will already have the cables stripped and screwed down with a place to connect other wires in an orderly fashion. then i'll just need to strip the individual ps/2 wires and screw them into the right places and plug the model-m into the wall plate.

about the ground, i think i agree... two grounds, or two wires connected together that serve as ground together? you think i should wire one up to a ground and the other to the PS/2 GND? i just hope i don't fry anything. i think i'll plug this into an old laptop to test before i go for my desktop  :Razz: 

well, more updates tomorrow when i get my female RJ-45. hope this works.

PS: thanks for all the help  :Very Happy: 

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## troymc

Good luck!

If we don't hear from you tomorrow we'll know your keyboard shorted and you're not online!     :Shocked: 

We may have to next-day air you a USB keyboard or some other emergency device!

troymc

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## MADcow

thanks   :Razz:  hopefully it won't come to that!

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## MADcow

i still haven't had any luck with it. i'm declaring it a dead keyboard.

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## gtbX

Some of the older model Ms come with a detachable cord with a RJ-looking connector on it - there are clips on either side instead of one on the top, and you can't mate it with an actual RJ-45 (Thats the connector I thought you were talking about when I first read your post).  There were both AT and PS/2 cables available, and I assume others.

I ran one of these cords through a continuity tester and this is what i got

red=power

black=ground

yellow=clk

white=data

I suggest you do the same with your ps/2 cord; not all manufacturers follow the same color codes.

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## MADcow

thanks for the tips! the cord is just like a normal rj-45, not like the one you described (which is SL?).

i don't have any kind of continuity tester, and i don't even know how i'd test it since i can't disconnect the other end of the wire from the keyboard...

i could do the ps/2, with a voltmeter or something, but my micrometer is very, very fritzy. i don't think i've gotten an accurate reading out of it in months. but i still get a reading. it's interesting, but i'm no electrician. or engineer. 

i'm thinking of buying myself a model M on ebay... i tried fiddling with the wiring on this one, but i can't get it to work. at least i haven't broken my PS/2 bus yet...

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## Doogman

You can actually buy new "Model M" style keyboards directly from the manufacturer at this site:

http://www.pckeyboard.com/

They aren't exactly cheap, but then Ebay Model M's aren't either.  Make sure to get the "buckling spring" design as that's the good keys with tactical feedback.  I've owned one for years and they are awesome.  Built like a tank.

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## gtbX

 *Doogman wrote:*   

> Make sure to get the "buckling spring" design as that's the good keys with tactical feedback. I've owned one for years and they are awesome. Built like a tank.

 

I used to have a newer version model M (i think the mfg date was 1995) that I wore out in a year.  Popped a key off and lo; it was the plastic-bubble kind found on lesser kb's.  Since then, if I find one at a garage sale or something I always check to make sure it is the metal spring kind.

MADcow:

If your voltmeter has a bell or diode setting, use that.  Otherwise "the poor man's continuity tester" consists of:

an old pc speaker

a AA battery

bits of wire to hook them together

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## bunder

dumb terminals use a serial interface.  you can buy a rj11 to serial adapter and hook it into your db9 serial port.

(i work at a place that uses lots of these)

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## MADcow

thank you, everyone for the tips. i think i'm going to check out buying one from [url]pckeyboards.com[/url] or ebay if i can't get this one working. i'm going to fiddle with the connections more this evening, but i'm not too hopeful...

Bunder: that sounds like what i need, but this connector is an rj-45   :Sad: 

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## MADcow

sorry to revive a very dead thread, but i found an RJ-45 to serial connector in my Big Box of Old Junk.

it's in good condition, but i don't seem to get any data on the serial port...

any ideas?

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