Abstract: An optical position encoder includes a scale having multiple tracks separated in a direction perpendicular to travel, the tracks including an incremental track and an absolute track, the scale interacting with an incident first light beam to generate a second light beam having components carrying respective optical patterns produced by the incremental track and absolute track respectively. The encoder further includes a set of optical detectors including at least first and second detector arrays of differing properties to detect the respective optical patterns produced by the incremental track and absolute track respectively, each of the first and second detector arrays spanning multiple tracks of the scale and configured to respond to a respective detector-specific component of the second light beam more strongly than to another component of the second beam specific to another of the detector arrays.

Abstract: An optical position encoder includes a scale having multiple tracks separated in a direction perpendicular to travel, the tracks including an incremental track and an absolute track, the scale interacting with an incident first light beam to generate a second light beam having components carrying respective optical patterns produced by the incremental track and absolute track respectively. The encoder further includes a set of optical detectors including at least first and second detector arrays of differing properties to detect the respective optical patterns produced by the incremental track and absolute track respectively, each of the first and second detector arrays spanning multiple tracks of the scale and configured to respond to a respective detector-specific component of the second light beam more strongly than to another component of the second beam specific to another of the detector arrays.

Abstract: The present invention relates to a communication device for a personal digital assistant (PDA). The PDA mounts within the communication device and the communication device connects electronically to a serial port on the PDA. Through this single serial port, the communication device provides the user of the PDA with access to multiple communication media, such as a telephone modem, a Global Positioning System engine, a packet radio and a cellular telephone. Data from the PDA is directed to a decoder that routes the data to the appropriate communication medium, while data from the communication media are multiplexed onto the single serial interface of the PDA. The communication device also provides a pass-thru serial interface that allows other external devices to communicate directly with the serial port of the PDA.