XT/AT/PS2/Terminal to USB Converter with NKRO

[vladafkv]

Hi! Im very happy that I finally got my hands on the IBM Model M keyboard. It was very dirty when it arrived so I had to fully disassemble it and do a bolt mod on it. Now I need help converting it to USB Type C. I bought a teensy off of ebay for $10 and type c connector board. I removed the SDL connector from the board and soldered teensy to it but I have trouble soldering type c connector board. I was following this guide : https://sudonull.com/post/17086-How-to-cook-IBM-Model-M

But its very hard for me to understand this part:

For our purposes, we need power (A4, B9, B4, A9), ground (A1, A12, B1, B12 and connector body), a pair for data transmission - D + (A6, B6) and D− (A7, B7). CC1 and CC2 must be connected to ground through resistors with a resistance of 5.1 kΩ. We connect to the stub of the USB cable bundled with Teensy: black - ground, red - power, green - D +, white - D−. A little plastic, superglue, electrical tape - and the connector is ready. Fix the tie and the keyboard is ready.

I believe this was translated from a russian website. Im not the best with understanding how this works. Can anyone help me?

I have the same components as seen in this guide.

[JBert]

While there are translation mistakes in the text (including the title), the bit you quoted actually looks correct.

Basically it refers to this USB C connector diagram:

mmmbbohpxsacjnr5v0xhagzly6g_usb_c_diagram.png

Here you can see that there are connector pins labeled A1 to A12, and pins B1 to B12. The text is thus instructing you to look up which holes in the USB C connector board you need to solder together and then on to which pin of the mini USB cable (which will go to the Teensy). A4, B9, B4, A9 are all "VBUS" / power pins. They should be all connected to the red wire in your USB cable. Same for (A1, A12, B1, B12) = ground = black cable; (A6, B6) = D+ = green cable; (A7, B7) = D- = white cable

Then CC1 and CC2 are the only ones left: here they mean that pin A5 needs a 5.1 kΩ resistor soldered to it with the other end of the resistor connected to ground (i.e. pin A1, A12, B1, B12 and the black USB cable). Another 5.1 kΩ resistor is connected to pin B5 with the other end also going to ground, and again connected in some way to all the ground pins and the black cable.

Once you get all those wires of the USB cable soldered then you can connect the Teensy and start testing.

EDIT: Well, before plugging in an USB cable it might be better to take out your multimeter and check that there is no short-circuit in your soldering, and verify that the right pins from the USB C connector board have been soldered.

[vladafkv]

Maybe a stupid question, but how do I connect 4 pins to 1 wire? Im new to this im sorry

diagram doesnt show up, it just says mmmbbohpxsacjnr5v0xhagzly6g_usb_c_diagram.png

[kelvinhall05]

Any idea if this will work with a Wang 725? If so, does someone have a pinout of the Wang's connector? Mine doesn't have the cable

[t8c]

Any idea if this will work with a Wang 725? If so, does someone have a pinout of the Wang's connector? Mine doesn't have the cable

Pinout is at the bottom http://sandy55.fc2web.com/keyboard/wang_724.html

[kelvinhall05]

Any idea if this will work with a Wang 725? If so, does someone have a pinout of the Wang's connector? Mine doesn't have the cable

Pinout is at the bottom http://sandy55.fc2web.com/keyboard/wang_724.html

You're a legend

Does it just speak AT or something? I will try wiring a converter up when it gets here

[Inxie]

I just want to personally thank Soarer for this honestly. I got my first IBM Model F (typing on it right now) and I was worried I was going to have problems adopting this for use on my modern PC, especially with the F's NKRO. Nope, I've been playing Doom Eternal on a Model F XT with Soarer's converter now for the past 12 hours, and not one beat skipped (just lost in the game's repetitiveness honestly). I am VERY impressed. You'd think this keyboard was natively USB, there's no sign that it's being converted. Even with print-screen by default being mapped to num pad *, I know people on GitHub thought this was incorrect, but actually it's very correct. Running CheckIt for DOS through DOSBox even passes the Print Screen key due to this, so this is correct behavior. It's Windows that simply doesn't treat it as Print Screen anymore (nothing Greenshot with a custom written .ini won't solve).

So yea, thank you Soarer for this, because now my first hand experience with a Model F in 2020 is perfect. (I last used a Model F when I was in elementary school in the early 90's).

[vladafkv]

I just want to personally thank Soarer for this honestly. I got my first IBM Model F (typing on it right now) and I was worried I was going to have problems adopting this for use on my modern PC, especially with the F's NKRO. Nope, I've been playing Doom Eternal on a Model F XT with Soarer's converter now for the past 12 hours, and not one beat skipped (just lost in the game's repetitiveness honestly). I am VERY impressed. You'd think this keyboard was natively USB, there's no sign that it's being converted. Even with print-screen by default being mapped to num pad *, I know people on GitHub thought this was incorrect, but actually it's very correct. Running CheckIt for DOS through DOSBox even passes the Print Screen key due to this, so this is correct behavior. It's Windows that simply doesn't treat it as Print Screen anymore (nothing Greenshot with a custom written .ini won't solve).

So yea, thank you Soarer for this, because now my first hand experience with a Model F in 2020 is perfect. (I last used a Model F when I was in elementary school in the early 90's).

what components did you use to convert it?

[Inxie]

what components did you use to convert it?

Mine was a pre-built on eBay, built into the USB plug itself. I believe they are the only authorized seller for them.

[fohat]

Orihalcon perfected his cable construction and my recollection is that he provides his own firmware programming instructions (in addition to Soarer's listed here).

Contact him via ebay or this forum and he will probably help you out.

[Hypersphere]

My first keyboard conversion project was an IBM-XT. I put a Teensy inside along with a flush-mount USB-B connector (I thought this heavy-duty board ought to have a more sustantial connector than a mini or micro USB). Programmed the Teensy with Soarer's converter. This XT is still one of my favorite keyboards.

I've also used cables with built-in converters as well as internal converters from Orihalcon -- I second fohat's recommendation -- Orihalcon makes excellent products.

[vladafkv]

My first keyboard conversion project was an IBM-XT. I put a Teensy inside along with a flush-mount USB-B connector (I thought this heavy-duty board ought to have a more sustantial connector than a mini or micro USB). Programmed the Teensy with Soarer's converter. This XT is still one of my favorite keyboards.

I've also used cables with built-in converters as well as internal converters from Orihalcon -- I second fohat's recommendation -- Orihalcon makes excellent products.

did you follow any guide or something?

[Hypersphere]

@vladafkv: Thanks for your question. No, I did not follow any particular guide for refurbishing my XT keyboard. I suppose I used a combination of intuition and tips gleaned from various posts in the Deskthority (DT) and Geekhack (GH) forums. For programming the Teensy with Soarer's converter, I did follow Soarer's posts and the Soarer's converter documentation along with guidance on the programming posted by Muirium.

[kelvinhall05]

Anyone know if this will work with a DEC LK201-like keyboard? Is the conversion for DEC protocol documented?