Abstract: A point of sale terminal is disclosed that provides all of the usual point of sale terminal functions, but that is entirely field portable. Data pertinent to each purchase can be input to the terminal via a keyboard assembly, a touch-screen display or a signature-capture screen assembly, or via an antenna and radio link from an associated bar code scanner. Data may be communicated at any time to a remote host computer, also via a separate antenna and radio link. The communication links with the host computer and the bar code scanner operate independently and simultaneously, using mutually compatible modulation schemes such as a spread spectrum scheme for the host computer link and a narrowband or spread spectrum scheme for the bar code scanner link. The terminal thereby functions as a portable repeater or node in a data communications network.

Abstract: A point of sale terminal is disclosed that provides all of the usual point of sale terminal functions, but that is entirely field portable. Data pertinent to each purchase can be input to the terminal via a keyboard assembly, a touch-screen display or a signature-capture screen assembly, or via an antenna and radio link from an associated bar code scanner. Data may be communicated at any time to a remote host computer, also via a separate antenna and radio link. The communication links with the host computer and the bar code scanner operate independently and simultaneously, using mutually compatible modulation schemes such as a spread spectrum scheme for the host computer link and a narrowband or spread spectrum scheme for the bar code scanner link. The terminal thereby functions as a portable repeater or node in a data communications network.

Abstract: A point of sale terminal is disclosed that provides all of the usual point of sale terminal functions, but that is entirely field portable. Data pertinent to each purchase can be input to the terminal via a keyboard assembly, a touch-screen display or a signature-capture screen assembly, or via an antenna and radio link from an associated bar code scanner. Data may be communicated at any time to a remote host computer, also via a separate antenna and radio link. The communication links with the host computer and the bar code scanner operate independently and simultaneously, using mutually compatible modulation schemes such as a spread spectrum scheme for the host computer link and a narrowband or spread spectrum scheme for the bar code scanner link. The terminal thereby functions as a portable repeater or node in a data communications network.

Abstract: An electric switch assembly for use with a magnetic reed switch includes a trigger that is movable with respect to a housing between an open position and a closed position and that includes a trigger magnet. The switch assembly further includes a second magnet, fixed relative to the housing, that is located adjacent the first magnet when the trigger is in the open position. The magnets are oriented such that their magnetic fields tend to cancel each other when the trigger is in its open position. This provides an increased disparity in the magnetic field reaching the magnetic reed switch between the open position and closed position and eliminates the need for precision alignment and individual adjustment of the magnetic reed switch at the point of manufacture.

Abstract: An encoding and decoding system for electronic data communication system, wherein each character to be transmitted is encoded as a unique multi-bit binary value. The total number of bits as well as the number of logic one bits in all unique multi-bit binary values are the same. A pulse generating means generates a wide pulse for each logic one and a narrow pulse for each logic zero. The pulses which make up a unique pulse form for each data character to be transmitted are of alternating polarity and are transmitted as analog signals.