Abstract: A writing system includes a pen with a two-dimensional optical sensor and a three dimensional acceleration sensor positioned to indicate movement of the pen. A calibrator is coupled to receive path coordinate signals from the two-dimensional optical sensor and the three dimensional acceleration sensor. The calibrator and the two-dimensional optical sensor and the three dimensional acceleration sensor are configured to operate in one of two modes, a contactable mode of operation wherein both the two-dimensional optical sensor and the three dimensional acceleration sensor supply path coordinate signals to the coordinator and a contactless mode of operation wherein only the three dimensional acceleration sensor supplies path coordinate signals to the coordinator.