US Patent 7006014 Computer system with passive wireless keyboard

A wireless keyboard and reader combination comprises a keyboard having a plurality of keys, an antenna, and a plurality of passive transponder circuits coupled to the antenna and associated with the keys. The passive transponder circuits are selectively coupled to receive power from the antenna and provide a coded response identifying a key in response to key activation. An associated reader includes a source of an interrogating field applied to the antenna of the keyboard and a decoder for determining the coded response from the passive transponder circuits.