Sources for 8b TTL keyboards (Keytronics)

[Glen Slick]

On Tue, Dec 9, 2008 at 7:38 AM, Jules Richardson
<jules.richardson99 at gmail.com> wrote:
>
> There must presumably be a USB keyboard protocol standard though (otherwise
> every USB-connected keyboard out there would need proprietary drivers) - so
> I assume that the more expensive PS/2-USB adapters really do interpret the
> PS/2 protocol and convert it to such a standard, and are primarily designed
> for keyboards which aren't natively USB-aware...
>

USB keyboards and mice are HID (Human Interface Device) devices and
there is a standard specification for these devices.  The active
PS/2-USB adapters appear to the host to be a standard HID which
unknown to the host speaks PS/2 to the keyboard and/or mouse.

http://www.usb.org/developers/hidpage/

http://www.usb.org/developers/devclass_docs/HID1_11.pdf

These specs are hard to understand but the actual device firmware
implementation isn't hard.