Abstract: The severity of the problems of transmitting high speed data over a regular twisted wire pair are legendary. These problems arise from a variety of conditions, including the capacitance of the wire (which increases with length) and the propensity of unshielded wire to pickup high induced voltages. An arrangement is disclosed that is suitable for short, as well as long, wire distances and which also effectively eliminates the interference problem caused by induced voltages, including those causes by electrostatic discharge. This arrangement passes two twisted wire pairs through a series of ferrite cores. The twisted wire pairs coming out of the ferrite cores are terminated such that one of the pairs is connected to ground while the signal carrying twisted pair is connected to a small signal balun coil, pulse shaping circuit and low pass filter.

Abstract: A self-initializing communication system is described which automatically itializes circuit boards of the system using predetermined operating parameters when the system is initially powered-up or reset. The system is arranged to initialize circuit boards inserted in any order in any board slots of the system equipment housing. A malfunctioning circuit board can be replaced while the system is operating and the replacement circuit board is automatically initialized by the system using the stored operating parameters from the malfunctioning circuit board.

Abstract: This invention is an interface arrangement which interconnects a business communication system with a telephone station set. This interface is implemented in a personal computer which serves to control the operation of the associated telephone station set and also provide business communication services. All signaling from the business communication system is received by the personal computer, interpreted, and appropriate control signals are then forwarded under control of the software resident on the personal computer to activate the digital telephone station set. The signals from the digital telephone station set are intercepted by the personal computer, interpreted, modified and appropriate control messages and signaling are then forwarded by the personal computer to the business communication system.This arrangement enables a user to create software on the personal computer to control the operation of the telephone station set associated with the personal computer.

Abstract: The UNIX.RTM. and MS-DOS.RTM. operating systems are supported in a multi-tasking computer. At the heart of the computer is a microprocessor having protected and non-protected modes. The computer includes special-purpose hardware which prevents the MS-DOS system and its applications, which execute in the non-protected mode, from interfering with the UNIX system and its applications, which execute in the protected mode. In particular, this hardware monitors addresses generated by the computer and, by selectively inhibiting the associated control pulses, prevents the MS-DOS system from, for example, writing in UNIX-system-allocated memory, or accessing I/O devices that the UNIX system is currently using. In addition, a context switching feature is provided whereby the user can select, via a keyboard operation, to have displayed on the computer video monitor at any given time the image generated from the current UNIX system screen data or the image generated from the current MS-DOS system screen data.

Abstract: The UNIX.RTM. and $MS-DOS sup R $ operating systems are supported in a multi-tasking computer. At the heart of the computer is a microprocessor having protected and non-protected modes. The computer includes special-purpose hardware which prevents the MS-DOS system and its applications, which execute in the non-protected mode, from interfering with the UNIX system and its applications, which execute in the protected mode. In particular, this hardware monitors addresses generated by the computer and, by selectively inhibiting the associated control pulses, prevents the MS-DOS system from, for example, writing in UNIX-system-allocated memory, or accessing I/O devices that the UNIX system is currently using. In addition, a context switching feature is provided whereby the user can select, via a keyboard operation, to have displayed on the computer video monitor at any given time the image generated from the current UNIX system screen data or the image generated from the current MS-DOS system screen data.

Abstract: In a multiprocessor system, processors are connected to an interconnecting bus by means of bus interface circuits which comprise an address buffer in addition to data buffers. The interconnecting bus, in addition to a destination address and data also carries an originating address identifying the processor transmitting the data. In the event of a receive buffer overload condition in the receiving bus interface circuit, a negative acknowledge signal is transmitted on the bus and the originating address is queued in the address buffer. When the buffer overflow condition has been relieved, a retransmission request is sent to the first processor identified in the address buffer and its message is received. This procedure will be repeated for each processor identified in the address buffer.

Abstract: A signaling arrangement where all terminal configuration data is stored in a switching system, but where each user terminal responds to a message from the system, defining one of the user terminal buttons as the selected call appearance at the terminal, by operating in a functional signaling mode to communicate with the system using functional messages concerning a call at the selected call appearance. Idle and ringing preference methods for use in terminating calls and auto-drop and auto-hold alternatives for use when moving from one call appearance to another are disclosed as well as methods for holding or dropping calls. Implicit and explicit conferencing methods are also disclosed.

Abstract: This message chronicling apparatus consists of a personal computer interposed between the principal's telephone station set and the port circuit of the business communication system which serves the principal's telephone station set. The personal computer intercepts all call signaling from the business communication system. The personal computer software collects the data so received and creates a record in the memory of the personal computer of the incoming call. The principal's personal computer not only interacts closely with the business communication system, but can also be interconnected in a local area network with other personal computers or terminal devices such that a user at one of the other devices or personal computers can create a call record for the principal's personal computer.

Abstract: An overhead optical scanner is disclosed which uses commerical 60 Hz AC powered fluorescent lighting apparatus to illuminate the scanned objects. The image sensor of the scanner operates at a line scan rate which is in sync with the 60 Hz rate. The image sensor integrates the variations in illumination intensity received from the object over one complete 60 Hz cycle, thereby producing an electrical signal which is characteristic of a uniformly illuminated object.

Abstract: There is disclosed an asynchronous pulse catching circuit that, for each edge of the variable frequency input, regardless of duty cycle, will provide a pulse, synchronized to a high speed clock. There is also disclosed a pulse comparison circuit consisting of a state machine that provides slip detection between the variable input frequency and a reference input frequency. The circuit provides separate outputs indicating positive and negative slip.

Abstract: A timing control arrangement that dynamically controls the distribution of iming information in a distributed digital communication system. A reference timing signal is distributed from a reference master node to all other nodes in the system. The distribution is accomplished on a dynamic basis without the use of a central control. Each node is connected by links to at least one other node and each node receives timing signals from all of the links to which it is connected. Each node selects one of these signals as its timing reference by scanning the various signals it receives to identify the one signal that is applied via a link path that is the "closest" to the master reference node as indicated by information specifying the number of intermediate nodes through which the timing signal has traveled from the reference node to reach the receiving node.

Abstract: This is an improved resistive line battery feed circuit where the improvement consists in establishing a balanced stable power point using an opamp and capacitive input and feeding the AC output to both lines of the tip and ring circuit via opamps and a hybrid for injecting current. In this manner longitudinal balance is maintained. Current is added to the line circuit by a modulated DC current source.

Abstract: An interface unit connected to one end of a communication path is arranged to conduct a transmission test of the path before exchanging information with an interface unit connected to the other end of the path and to signal the results of the test by terminating the test when the results show an absence of transmission errors and continuing the test when the results show the presence of such errors, the test being the transmission and reception of a predefined sequence of signals.

Abstract: A system has been devised that allows commonly used software components to be designed and developed only once, and reused many times in different applications with different operational contexts and requirements. The system includes a language for the specification of software components in a context-independent generic fashion, a compiler for the specification language and a program for generating concrete software components to work in a specific context.

Abstract: The integrated calling directory of the present invention eliminates the disadvantages of prior call directory arrangements by providing a software system which runs on a personal computer to automate the call directory and call origination function. The personal computer is interposed between an individual's telephone station set and the business communication system port circuit associated with the individual's telephone station set. The calling directory software both contains the individual's personal directory entries and has access to directory entries in the centralized business communication system data base which resides on an adjunct processor. These directory entries all contain called party identification data which includes information such as an individual's name, room number, electronic mail address, telephone number, type of terminal equipment associated with the called party, job title, etc.

Abstract: Apparatus for and a method of inserting circuit switch information and packetized data into different time slots of a time division multiplexed bus. A memory having a location individual to each time slot is written with information specifying whether the time slot individual to each location is to serve circuit switch information or packet data. The readout of each memory location during the occurrence of it's associated time slot controllably effects the application of either the circuit switch information or the packet data to the bus. Packet data can be inserted into each time slot not currently being used by the circuit switch. A special information bit is inserted into each time slot to specify whether the remainder of the bits of the time slot represents circuit switch or packet information. The information bit is used by receiving apparatus to steer the bits of each time slot to either a receiving circuit switch or a receiving packet switch.

Abstract: This invention provides an audible indication to a held party indicating when a call is removed from the hold state. Heretofore, when two parties on a call are in a talk state and a first party puts a second party on hold, the held party must aurally monitor the receiver on the station set for the first party's voice to detect when the talk state is resumed. The voice of the first party provides the only indication that the hold condition has been removed. This requires the held party to monitor the receiver for the duration of the hold state and prevents the held party from easily pursuing any other activities. The subject arrangement overcomes this problem by providing a "ring-ping" signal to the held party when the hold condition is removed. In particular, following the activation of the hold condition by the first party, the held party leaves the receiver off-hook and can then pursue other activities.