Abstract: A personal identification instrument is comprised of a substrate, and carried on the substrate: a photograph and/or a personal signature, personal information relating to the legitimate holder of the instrument, and an encrypted machine readable security code carried by the instrument, the code being comprised of a combination of digitized personal information and a digitized descriptor of the photograph and/or personal signature.

Abstract: A method is provided for transmitting and/or receiving files via a facsimile machine or computer fax modem. Electronic binary files residing on a computer, for example executable files, word processing files, database files and other types of files are converted to a machine readable binary bitmap in the form of a black and white bar code. Preferably the converted file is encrypted before being transmitted and printed. A receiving computer fax modem or facsimile machine can then print the file for later retransmission or storage, or a computer fax modem can reconstruct the file so that it can be used and/or executed after being received.

Abstract: A first terminal for use in a time division duplex communication system comprising apparatus for automatically, successively, repetitively and alternatingly transmitting and receiving compressed signals to and from another terminal via a single transmit and receive time divided channel, including apparatus for changing a transmit and receive mode of the first terminal in synchronism with an opposite transmit and receive mode of another terminal, apparatus for receiving a timing signal which is the same timing signal received by another terminal, and apparatus for changing the mode at intervals determined from reception of the timing signal.

Abstract: At each of a pair of linked terminals, an image is generated at local and remote input devices. The generated image is projected onto a viewing screen and, while exhibited, further locally or remotely generated data is used to alter the generated image and, consequently, to alter the projected image. Data can, for example, be generated by means of a document scanner and a manually operated X-Y pen digitizer.

Abstract: A matrix multiplexed field effect display has switch devices at matrix crosspoints to provide a turn-on threshold for the field effect material. The switch devices are thin film metal-insulator-metal (MIM) switches. The display is operated at low current so that the MIM switches, which may be deposited on glass, do not degrade rapidly in use.

Abstract: A matrix multiplexed display cell has thin film switch devices at matrix crosspoints to provide a turn-on threshold for electrooptic liquid used in the cell. Each of the switch devices has two parallel branches of diodes, the diodes in one branch being of reverse polarity to those in the other. The cell is operated at low current so that the switch devices, which are deposited on glass, do not degrade rapidly in use.

Abstract: A matrix multiplexed display cell has thin film switch devices at matrix crosspoints to provide a turn-on threshold for the electro-optic liquid used in the cell. Each of the switch devices is a back-to-back pair of diodes. The cell is operated at low current so that the switch devices, which are deposited on glass, do not degrade rapidly in use.

Abstract: Each element of a display operated in a scan mode is series connected to a thick film switch which sets a voltage threshold to isolate the element from periodic scan pulses unless coincident with an element selecting data pulse in which case the thick film switches and the element, for example, a nematic liquid crystal cell, operates.