An authenticator device designed to preclude undetected compensating text modifications in a message by sequentially processing each character of the message and producing an authenticator code as a result of said processing. As each message is received, it is modulo added to the contents of a first register and the result is used to simultaneously address first and second memories, the values stored in the first memory consisting of a specified permutation of preselected decimal values, the val...

A base drive circuit particularly well adapted for use with bipolar transistors in high frequency power conversion schemes. The base drive circuit allows achieving desired values for both forward and reverse base drive currents simultaneously regardless of the characteristics of the bipolar transistor driven. When utilized in a transformer isolated inverter system, the base drive circuit additionally presents a polarity insensitive input impedance which eliminates the effects of cross-conduction...

A base drive circuit particularly well adapted for use with bipolar power transistors in high frequency power conversion systems. When utilized in a transformer isolated inverter system, the base drive circuits present a polarity insensitive input impedance which eliminates the effects of cross-conduction between base drive circuits connected to the secondary side of the transformer.

An apparatus for dispensing groups of integrated circuit (IC) packages in a pattern and quantity corresponding to the pattern of unpopulated IC sockets on a printed circuit board. The apparatus includes a plurality of storage racks stacked one on top of another, with each rack corresponding to one row of socket positions on the unpopulated printed circuit board. Each storage rack includes a number of loaded IC dispenser magazines corresponding to the number of positions in that rack's correspond...

A circuit for accurately reconstructing the timing information encoded within digital waveforms of the double frequency class includes facilities for restoring the circuit to proper synchronization at start up time or after a burst of noise on an incoming waveform. The circuit first generates three delayed versions of the incoming double frequency waveform. Transitions in the incoming waveform are detected by comparing the incoming waveform with the first delayed waveform and simultaneously comp...

A circuit arrangement for extracting clocking signals from double frequency encoded transition-event waveforms. The incoming waveform is fed directly into a digital delay line which generates three versions of the incoming waveform, each delayed by 1/4, 1/2 and 3/4 of the incoming waveform's bit cell time, respectively. Transitions in the incoming waveform are detected by comparing the output of the first delay line tap with the incoming waveform and simultaneously comparing the outputs of the s...

A device for generating an authenticator code by encrypting the contents of a plain text message in accordance with a unique user supplied authenticator key variable. The device operates in two phases, the first of which processes every character in the plain text message and produces a first sequence of 16 check bits. The second phase processes this first 16 check bit sequence and transforms it into a second sequence of 16 check bits which may be utilized as an authenticator code.

A device for use with a digital computer for storing standard software used by the computer and modifying the address portions of the standard software prior to transmission to the computer. The device includes a ROM package containing a ROM within which is stored a standard software subprogram written assuming it is stored at an absolute location in the computer's memory other than its actual location in the computer's memory system. Also included in the ROM package is a base register which can...

A multiloop communications system and a method of routing data between stations is disclosed. The communications system has a plurality of interconnected communications loops, each of the loops including a ring-connected set of nodes providing data flow unidirectionally from one node to the next, each of the nodes being capable of passing data through itself along its loop, extracting data from its loop or injecting data into its loop. A first subset of each loop's set of nodes are local nodes w...

A device for insertion in a communications line for verifying message integrity within a significant portion of existing communications networks. At the transmitter end, the device receives plain text messages from the communications line, generates an authentication field by encrypting the plain text message received and retransmits the plain test message received, with the authentication field appended thereto, onto the communications line. At the receiver end, the device receives messages fro...