Question about keyboard for cnc build

Hello I’m building a controller for a small cnc mill, I have most of the parts I need apart from a suitable panel mount keyboard.
I have a denford desk top tutor keyboard I got with my machine, it’s connected via parallel port it originally used a 25 pin to 9 pin serial adaptor to connect it to the pc, and has changeable overlays, and would have originally been used with dos drivers to make it work. I’ve opened it up and it would make an excellent panel mount membrane style keyboard, with the added bonus I could make my own custom overlay with all the buttons I need.
I was wondering if it would be possible to Interface this keyboard and make it work with my linuxcnc system.
Many thanks
Lee

andypugh wrote:

All things are possible, but some are easier than others.

Do you know anything at all about the serial protocol used?

(And are you sure that it is a parallel to serial adaptor, and not just a Serial-25-pin to serial-9-pin adaptor? Back in the old days serial ports were 25 pin.)

Hello, in fact you are correct about the adapter, it is a 25 to 9 pin adapter. I think I read somewhere that is is an rs232 plus a couple of extra wires (possibly power wires) thrown in. I’m led to believe that the keyboard originally used a ‘.keys’ file and I’m guessing that would be a driver or decoder.

Many thanks

Preferably I would love an all in one solution, so that I could have all the control in one enclosure without the need for a separate keyboard, but at the same same it wouldn’t be a big problem to add a usb socket to the enclosure and use a standard keyboard. Ideally a full panel mount membrane style keyboard to fit on my panel of no more than 400mm wide, but that’s really a long shot unless I can salvage something from the depths of eBay..

Thankyou, im not sure what you mean by user space text entry?

Author says the project is for Barcode scanner, but maybe it could be adapted if you can find the protocol of the keyboard you have.

github.com/theatrus/softwedge

Also found this, maybe of use

www.denfordata.com/bb/viewtopic.php?t=3103

I've got one of these, with the intention of using it as a nice console...

It's serial - it has a DB25 port like all Denford stuff had (don't think they ever knew about DB9s), but just needs a basic adapter.

Checking the circuitry out, can confirm it's a very simple two-wire RX/TX, plus ground, and then uses the RX/DTS/RTS for power from the host.

Using screen, or something similar (I'm using CoolTerm), you can get the HEX and ASCII output - and it's simply ASCII corresponding to each button. Nicely there's a button down character and a button up character (handy for modifiers, and repeating an entry until the up character is received). The character is sent only once on either down or up, no repeats etc like a keyboard.

Mine is the fixed variety, so no "overlays" which the later models had (they were a grid of buttons, and plastic overlay cards with the graphics on them). Those are the same, but there's a predefined grid corresponding to the ASCII generated, and each "overlay" had a mapping file accordingly. But, hooking this to a serial converter/port, and watching the ASCII is the easiest way of figuring out what each button generates.

So, my thought is a simple Python script etc to take the ASCII, map it etc and then send it to a pipe, for some function in LXCNC to listen to. The only thing I'm trying to figure out, is how to enable the 2x LED (one for "coolant on" and the other for "external keyboard").

They'll be ASCII I'm sure, but need to figure out what they are.

All in all, quite a nice input device given how cheap they are, and simple they are to get working. I'd class them as "driverless", as they produce ASCII, and you just need to map the ASCII somehow...