Matrix Orbital Corp

Hi,
I have the LK404-AT unit - 40x4 lines with AT keyboard connector on the rear.
Background is I have removed the large AT socket from the circuit-board (as it makes the module too deep to fit in the box I want to use!) and have connected the solder points to an external PS/2 style keyboard socket on my outer box. I also have a USB/Serial converter on the end of the serial interface cable from the device so I can connect via USB to my PC.

This all works great - I can connect a standard PS/2 PC Keyboard and run a standard comms program on my PC and key presses appear as expected.

However I also have a barcode scanner of the "keyboard wedge" type - so it plugs into the keyboard socket and the keyboard then piggy-backs on this. The keyboard works fine as before - however if I attempt to scan a barcode I would expect the PC to recieve the digits of the barcode as if they had been typed on the keyboard - this is what happens if I connect the same keyboard/barcode scanner to my PCs keyboard socket!

However when connect via the LK404-AT the digits from the barcode scanner appear as garbage on the comms program screen - I thought it might have been corrupting the keycode values in some way - but I'm not sure. The only difference between keypresses on the keyboard and a scanned barcode I can see is that the barcode scanner would send its "keypresses" much more quickly. It's possible to change the "character delay" that the barcode scanner uses - anything up to about 1/2second between digits - but it doesn't seem to help?

I'm wondering if anyone else has had similar problems or has any ideas what's going wrong?

Also I notice that this module is/has been discontinued and there doesn't seem to be a direct replacement (ie. device that directly accepts a normal keyboard). Any suggestions on alternatives?

Hi David,

To answer you question, I will tell you a little bit about how a key is sensed on the unit. When a key is pressed a row and column is physically shorted, and the short will be detected by the microcontroller, and an ascii character is generated afterwards.

If you use a barcode scanner, the technology is totally different. There is no way to get a row and column to physically short together, so the barcode scanner can't work with the display.

I hope this clears things up for you.

Since the unit you are talking about is discontinued, maybe you can try using a keypad instead.

Best Regards,

HI Tom,

Thanks for that. However my barcode scanner has a keyboard connector on the end of its lead and can be conencted to a PC Keyboard socket - so it effectively is a keyboard as far as the connecting device is concerened.

I was disappointed that this unit is discontinued as it seems to be the only one you did with a full keyboard connection. The application I'm using the LCD for requires a full size keyboard for data input and this was the ideal solution.

Is there any other unit that offers full keyboard connection? Or can you suggest another solution?

Hello David, the LK404-AT is our only unit with the full keyboard connector capability and it is discontinued.....however, we do have some excess stock available. We will sell the LK404-AT units until the stock is depleted so please feel free to place a volume order a.s.a.p. to take care of your future needs.

Regards,
Bernadine