Hello to all the forum members!
The keyboard model is Compaq MX 11800:
http://deskthority.net/wiki/Cherry_G80-11800The adapter that I'm using is similar to this:
http://www.vpi.us/images/usb-ps2-lc.jpgGenerally this setup works fine, except for these problems:
- Sometimes the pressed key is "stuck", and sent to PC until some key is pressed. Results in something like thisssssssssssssssss.
- Sometimes the pressed key is not sent to PC at all. Results in something like ths.
- When playing games which require constantly pressed key (like FPS moving forward), pressing another key may (or may not) "unpress" the pressed key, so it needs to be pressed again.
This is for sure not the keyboard fault, since I've worked with this keyboard for couple of years on a PC with PS/2 ports and never had those issues.
After digging some info on the net, I came up with this article, on which only the last paragraph is interesting:
Why you can't use a third-party PS/2 to USB adaptor:
The I-PAC is a native USB device which auto-detects the interface (USB or PS/2) and invokes a completely different firmware module in the chip accordingly. Some converters are made by companies such as Belkin, which have chips which convert PS/2 into USB. These cannot be used. To understand why, we have to realize that the way in which keystrokes are sent via PS/2 is different to USB. PS/2 protocol sends "Key Down" and "Key Up" commands. In USB, the data sent to the PC is a description of all keys which are pressed at the time. For this reason, the designers of these converters are faced with a problem of potential "stuck keys" in USB, beacuse many PS/2 keyboards intermittently fail to send all of the "key up" commands. A missing "key up" will cause a stuck key in USB which will repeat forever and completely mess up the PC. So what the converters do is cancel all pressed keys from the USB packet every 5 seconds or so, just in case any "key up" commands were missed. So if you are holding the joystick in one direction, the movement will stop after a few seconds.
Also, the USB converters suffer from the same 6-key-pressed limit of standard USB keyboards, whic the I-PAC, in USB mode, does not suffer from.
Source:
http://www.ultimarc.com/usb_vs_ps2.htmlI guess some more sophisticated converter should be used. Maybe something like those:
http://www.aten-usa.com/products/productItem.php?model_no=UC100KMA#.VQxCQOlsZB1http://www.clickykeyboard.com/_ebay/modelm_usb/modelm_usb-001.jpgSo my questions are:
- Is this behavior is known to someone?
- Which adapter/converter would work for sure without problems?
Thanks!
