deskthority

I just bought an interesting Nixdorf Keyboard.
More general info here: https://www.reddit.com/r/MechanicalKeyb ... _keyboard/


Here are some pictures about the connector and some internals: https://drive.google.com/drive/folders/ ... sp=sharing
Is there a way to possibly convert this to usb?

ah, you got yourself a fine G80-0801, nice ! I'm not sure about USB conversion actually, for what it's worth sixty attempted to convert it to USB, no idea what came out of that

viewtopic.php?p=10340#p10340

from what I understand it shouldn't be too hard since it's serial (?)

Myoth wrote: 10 Apr 2021, 21:12 from what I understand it shouldn't be too hard since it's serial (?)

Well, I think to convert I just have to add somehow an U to the Serial Bus.

coolrainbow20 wrote: 12 Apr 2021, 22:21

Myoth wrote: 10 Apr 2021, 21:12 from what I understand it shouldn't be too hard since it's serial (?)

Well, I think to convert I just have to add somehow an U to the Serial Bus.

Fair enough haha but what exactly ? I don't think it would be as easy to just wire correctly a RS232 to USB "converter", surely there should be some kind of protocol conversion ?

Just wanted to post an update on this keyboard: I'm currently in the way of creating some technical images showing the wires/connector pinout and some more technical stuff that hopefully will help me and others to convert this keyboard to usb.

Here is some work in progress: https://drive.google.com/file/d/1wFdw-i ... sp=sharing

The Pin assignment is from Wikipedia. I'm not sure if the pin assignment is the same or not. At least the DB9-Plug seems to have the pin numbers at the default location. Also I find it pretty interesting to have a male plug at the device side. Normally it is the other way around, like with a female port on a serial mouse, and a male port at the computer side.

I hesitate to say never or anything so categorial about vintage electronics. But it is unusual to have RS-232 levels between a terminal and a keyboard. The cable is so short, there isn't any need for the signal integrity this buys one. Also, I don't see anything on the photos that would obviously be able to generate the needed voltages. Remember that ±5V would be the easiest and real RS-232 might even be ±15V.

It probably is some kind of bit serial, since 9 pins isn't enough for anything else. It might even be standard 1 start bit + 8 data bits + 1 stop bit. But likely at TTL levels, that is, +5V vs. 0 (or vice versa).

And it probably completely ignores what the normal pin assignments are on a DE-9.

MMcM wrote: 28 Apr 2021, 23:23 I hesitate to say never or anything so categorial about vintage electronics. But it is unusual to have RS-232 levels between a terminal and a keyboard. The cable is so short, there isn't any need for the signal integrity this buys one. Also, I don't see anything on the photos that would obviously be able to generate the needed voltages. Remember that ±5V would be the easiest and real RS-232 might even be ±15V.

It probably is some kind of bit serial, since 9 pins isn't enough for anything else. It might even be standard 1 start bit + 8 data bits + 1 stop bit. But likely at TTL levels, that is, +5V vs. 0 (or vice versa).

And it probably completely ignores what the normal pin assignments are on a DE-9.

So you're saying it's difficult to convert?

coolrainbow20 wrote: 29 Apr 2021, 10:40 So you're saying it's difficult to convert?

No, just that you're probably wasting your time if you think that its use of a DE9 connector would be in any way related to the use of a DE9 connector on a completely unrelated system.

I progressed in making this Keyboard to work. More stuff here: https://www.reddit.com/r/AskElectronics ... ?context=3

I already found out that this Keyboard is powered with 5V on the pin 6 and pin 5 is Ground, the other two pins (pin 1 and pin 3) don't output any clock and data signals, instead the system where this keyboard came from did the communication.

Okay, I had a chance to look at a G80-0801.

First, to make sure that the numbering is consistent. I believe that in the close-up photo on Google Drive linked to above, it shows how S1 is numbered, with 1 at the top-left then 2 beside it. I therefore read the pinout as follows.

• S1:2 - DE-9:1 - green
• S1:3 - DE-9:6 - white
• S1:5 - DE-9:7 - brown
• S1:6 - DE-9:2 - yellow

I will use those numbers below.

• pin 6 is indeed +5V
• pin 2 is the always connected ground
• pin 5 is connected to ground if the switch is depressed, which is why it may have appeared to be ground
• pin 3 is the data line

Here is the back of the PCB: Focusing first on the power daughter-card in the upper-right, the button connects pairs of pins horizontally. This powers the LED in the corner and also grounds pin 5.

The data line is unidirectional. It only goes to pin 10 of U2, an inverter. It can be seen here snaking over down and to the left of that chip. And in one of the other photos going underneath it on the other side.

Pin 11 of U2 is connected to pin 38 of U4, the 8039. This is P27, the high bit of port 2. So, the data output is that inverted (and cleaned up).

As for what that data is, it's TTL level serial, idle high, 2400 baud. And it's ASCII, more or less. Specifically, it's some German codepage where ä is {, ö |, ü }, ẞ ~. All the cool function keys are just "characters" with the eighth bit set, as are the ALT forms of the letters.

There is no key release transitions or shift states exposed. CTRL is ASCII control.

A proper USB converter will need a new controller.

An interesting Nixdorf Keyboard.

I have heard of vintage white but I can't recall having seen a typing demo of a vintage white keyboard.

MMcM wrote: 13 Mar 2022, 22:24 A proper USB converter will need a new controller.

So you are saying that the keyboard controller isn't intelligent enough for a converter and thus needs a more intelligent controller, right?

Well in that case we need to look at the traces, in order to redraw the matrix in some readable format for the new controller, and then de-solder any component, so we can solder in the new controller at the right spot and then just program the controller with the matrix information we captured earlier. I think that it is possible to reuse all LED's, the extra power switch and the coiled cable. Since the cable has 4 wires, we can use these to let the usb signals and power lines to go through it. On the Serial port end we need a serial to usb adapter (passive only, no electronics inside).

Also what I found out is that the capslock key can only be disabled (once enabled) by pressing either of the shift keys. This behavior is very german like and not IBM like. Back in these days the IBM layout was also called the EDV layout in German (Elektronische Datenverarbeitung) (electronical data manipulation). This keyboard seems to be for Bildschirmtext (according to the keycap-legends, Bildschirmtext was a German predecessor to the internet). The layout somewhat resembles an IBM Model F AT (10 F Keys on the right) mixed together with an IBM Model M layout (extra navigation cluster, extra keys above the alpha block).

Edit: This keyboard even has N-Key-Rollover, every switch has a diode in it and the capslock key an l.e. diode. Pretty cool old german extra. I think cherry did that to many other boards they made too.

Yes. You described a controller replacement. The first step is mapping out the matrix and then choosing the right Teensy or the like to install in the original controller’s place.

I’ve traced a few matrices recently. You get the hang of it. Pics here:

viewtopic.php?p=497915#p497915