Contact pen and data processing system structure for and based on pen-input computer system

An architecture is disclosed for communication of remote devices to a digitizing display. The architecture includes a contact sensing erasure mechanism and a position sensing erasure mechanism whose outputs are multiplexed for transmission from the stylus to an antenna located proximate to the digitizing display. The digitizing display will erase text or graphics data in a pen-based computer system in response to the stylus. A calibration method provides improved accuracy for the erasure function.