Ps/2 to usb keyboard adaptor supporting n-key rollover

A method for converting keyboard signals, comprising:

• (a) receiving electrical signals representing key press information;
• (b) generating keyboard data packets complying with a USB (universal serial bus) standard based on the received electrical signals, each keyboard data packet having a format of nine bytes or longer and representing up to eight modifier keys and seven or more non-modifier keys;
• and
• (c) transmitting the keyboard data packets to a USB host, wherein each keyboard data packet is transmitted as one or multiple USB data packets in one or multiple consecutive USB polling periods.

A KVM (keyboard, video, mouse) switch device, comprising:

• a converter module for receiving electrical signals representing key press information and generating keyboard data packets complying with a USB (universal serial bus) standard, each keyboard data packet having a format of nine bytes or longer and representing up to eight modifier keys and seven or more non-modifier keys;
• a plurality of USB device controller modules each for transmitting the keyboard data packets to a USB host, each USB device controller module receiving polling tokens from the corresponding USB host and transmitting each keyboard data packet as one or multiple USB data packets in one or multiple consecutive USB polling periods to the corresponding USB host;
• and
• a switch circuit for transferring the keyboard data packets from the converter module to a selected one of the USB device controller modules.