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Author Topic: IBM Model M M122 Terminal Unit - Dip Switch Help  (Read 2190 times)

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Offline diazel

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IBM Model M M122 Terminal Unit - Dip Switch Help
« on: Thu, 10 September 2020, 09:10:16 »
So I bought a M122 Model M on eBay with the intent to convert to USB via pro-micro. Since the cord was cut when I bought it, made the perfect donor to snip off and wire directly to Promicro so I don't have to make a separate housing to hold the guts, woot!

The question that I have doesn't directly tie to the mods but the bottom of the case has a dip switch bank with 8 switches but when I open up the case, it's not connected to anything. It's just hanging out there in the ether. I also didn't immediately see where I could even connect it. There's bank of 90 degree pins coming off the controller which, presumably, would be where it connected but the pins and the female connector on the dip switches are not compatible. I can't seem to find a picture of the dip switches wired up and I'm feeling like an idiot. Is there a wire extension that I'm missing? Did these ever ship with the dip switches in place but unused and not connected?

IBM Model M M122
PN: 1389160 - 1986
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Offline yui

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Re: IBM Model M M122 Terminal Unit - Dip Switch Help
« Reply #1 on: Thu, 10 September 2020, 09:38:18 »
my M122 is too recent to have the dip switches but reading soarer's converter post you i saw that those existed, and if i recall correctly they set the keyboard identifier, i don't really know why it was needed in the 1st place and i do not think it should be a problem for your conversion, as with it not wired is equivalent to all switches being at 0.
that's all i know and hope this helps, else fohat may give better info later
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Offline fohat.digs

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Re: IBM Model M M122 Terminal Unit - Dip Switch Help
« Reply #2 on: Thu, 10 September 2020, 10:02:53 »
HA HA

I am not the great guru of IBMs. I have had a number of F-122s with that bank of switches and they have not been connected to anything. I just ignore them but leave them in place because they look cool.
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Offline diazel

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Re: IBM Model M M122 Terminal Unit - Dip Switch Help
« Reply #3 on: Thu, 10 September 2020, 10:11:16 »
Fascinating. So this transcends multiple models too. You'd think that if they weren't even going to be connected then it might have saved them a bit by snapping in a blank as opposed to the plastic bracket, dip switches, and wiring harness to nowhere.

For no other reason than the dipswitches have presumably never been connected, I think I'm going to bring them into the promicro and make them do something stupid. Hadn't gotten this far yet but I was curious what it would take to convert it to bluetooth by adding a module. Maybe I could use one of the dipswitches as the power switch for that.
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Offline fohat.digs

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Re: IBM Model M M122 Terminal Unit - Dip Switch Help
« Reply #4 on: Thu, 10 September 2020, 10:28:43 »
Back in the day there was a plethora of IBM hardware and their philosophy was to make components adaptable to a wide set of environments.

Lucky for us, it makes tasks like converting ANSI to ISO or changing double-width keys to singles, and vice-versa, trivial once the inner assembly is apart.

My guess is that those switches could be set to allow the keyboard to talk to a variety of older mainframes and mini-computers.

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"The Trump campaign announced in a letter that Republican candidates and committees are now expected to pay “a minimum of 5% of all fundraising solicitations to Trump National Committee JFC” for using his “name, image, and likeness in fundraising solicitations.”
“Any split that is higher than 5%,” the letter states, “will be seen favorably by the RNC and President Trump's campaign and is routinely reported to the highest levels of leadership within both organizations.”"

Offline diazel

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Re: IBM Model M M122 Terminal Unit - Dip Switch Help
« Reply #5 on: Thu, 10 September 2020, 11:25:54 »
THIS IS THE WORST! Now I'm going to be sitting here wondering about all the possibilities!
No, overall it makes sense. Given the price tag on these things back then, even non-feature features probably helped to keep that pricetag high.

Quote from: fohat.digs on Thu, 10 September 2020, 10:28:43
Back in the day there was a plethora of IBM hardware and their philosophy was to make components adaptable to a wide set of environments.

Lucky for us, it makes tasks like converting ANSI to ISO or changing double-width keys to singles, and vice-versa, trivial once the inner assembly is apart.

My guess is that those switches could be set to allow the keyboard to talk to a variety of older mainframes and mini-computers.
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Offline fadiayad

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Re: IBM Model M M122 Terminal Unit - Dip Switch Help
« Reply #6 on: Sat, 19 September 2020, 19:50:20 »
Hello,

I have my own model M 122 terminal keyboard model number 1395660 made in USA 1992
I bought it for parts, I fixed the assembly with bolts. converted from ISO to ANSI.

I removed the controller board completely. and I made my own PCB at home which has a QMK firmware that i ported for this keyboard. and now it is USB connected with a USB port on the back of the keyboard. I customize the extra keys to perform other function that I need for my work and it works extremely well. I also added the lock LEDS on it.
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Offline fohat.digs

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Re: IBM Model M M122 Terminal Unit - Dip Switch Help
« Reply #7 on: Sat, 19 September 2020, 20:54:21 »
Very nice!
Impressive work.
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"The Trump campaign announced in a letter that Republican candidates and committees are now expected to pay “a minimum of 5% of all fundraising solicitations to Trump National Committee JFC” for using his “name, image, and likeness in fundraising solicitations.”
“Any split that is higher than 5%,” the letter states, “will be seen favorably by the RNC and President Trump's campaign and is routinely reported to the highest levels of leadership within both organizations.”"

Offline fadiayad

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Re: IBM Model M M122 Terminal Unit - Dip Switch Help
« Reply #8 on: Sat, 19 September 2020, 22:02:24 »
Thank you.

I bought two of the model M 122 for parts, these images are for the first one I repaired. I will only keep one of them, so eventually I will do the same to the second one and sell it.


Quote from: fohat.digs on Sat, 19 September 2020, 20:54:21
Very nice!
Impressive work.
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