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: 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: There is disclosed an arrangement which enables a single modem port to be used for either synchronous or asynchronous data transmission, with no manual changes required. The modem determines whether the incoming call is synchronous or asynchronous by detecting the presence (or absence) of SYNC characters in the data stream immediately after handshaking. Once a determination has been made, the modem options itself accordingly for synchronous or asynchronous data handling. This arrangement eliminates the need for separate central office lines for synchronous and asynchronous data applications.

Abstract: There is disclosed a clock circuit for a PBX system that uses phase locked loop technology to perform synchronization between two input signals. The system can switch between different reference sources without introducing error and without requiring the entire circuit to become realigned with the phase of the newly selected reference signal. This is accomplished with a phase build-out circuit that uses a phase locked loop divider to change the phase of the internal control signal to match the phase of the newly selected reference thereby eliminating timing changes on the system clock bus. The system can also be used to change between redundant clock circuits.

Abstract: There is disclosed a method of setting up, manipulating, and taking down communication connections. The telephone instrument would include a graphics screen, such as a PC, and a series of call appearance boxes would be represented on the screen. Each possible party to a connection would be represented by a picture (icon generated upon request for a particular party) and an associated label (the party's name). The icon representative of a party is moved, by use of a cursor, inside a communication appearance box on the screen to place that party on the call. The icon would be moved out of the box to drop the party from the call. In this manner, two-party, as well as conference, calls can be established.

Abstract: A power adapter is disclosed for use in connecting electrical power to a telephone station via a cross-connect jack. The power adapter has a plug-end for mating with the cross-connect field and a jack-end for receiving a cross-connect patch cord. The power adapter includes a two-conductor permanently attached power cord. Bent wire technology is used to connect the contacts of the receiving jack with the contacts of the plug while blade insertion technology is used for making contact with the ends of the power conductors.

Abstract: There is disclosed an interrupt arrangement for use in a multiprocessing system where it is desired to specifically direct interrupts from one processor to any other processor. The arrangement treats the interrupt signal as a data communication between processors. In this regard, common address space is set aside, on a system basis, for interrupt signals. A sending processor first contends for the system bus and then addresses a message to a specific target processor. The message is received at the target processor over the regular communication channel and stored in a FIFO memory. Interrupt messages filter through the memory in order of arrival and cause interrupts to occur at the target processor. The information at the output of the FIFO memory controls the processing of the interrupt.

Abstract: Encryption systems typically rely on the distribution of cipher keys between terminals for scrambling and unscrambling transmitted messages. Elaborate security precautions are necessary to protect the cipher keys since a compromise of the key could result in a compromise of the transmission. There is disclosed a key distribution method and apparatus which uses a channel from identified terminals to a central key distribution center for the establishment, on a one-session basis, of the key which is to be used for the next session between those terminals. The key establishing link is itself encoded using a cipher key which changes after each usage. Provision is made to verify, for each new connection, that a compromise has not priorly occurred.

Abstract: A new soldering technique is being employed whereby solder is formed into pads, each pad connected to the next pad by a solder link. The pads are formed on center spacings equal to the spaces between assembly board terminals and heated to the melting point of the solder whereupon surface tension of the solder collapses the interconnecting pad links thereby leaving the terminals electrically isolated. The solder pad assembly is made by an etching process.

Abstract: Resistive battery feed circuits are normally not used because of lack of power supply noise rejection and attendant crosstalk coupling. In this circuit the opamp and surrounding circuitry insure that power supply and ground noise do not couple into the tip and ring circuits as a metallic signal and improve crosstalk attenuation. In addition, the opamp is used to split the 48 volt supply.

Abstract: A touch sensitive device is arranged with substantially parallel surfaces inside which light from a synchronized source, such as a CRT, can become trapped by total internal reflection. The screen is fitted with photodetectors which respond to the entrapment of light within the surfaces. The device is compliant so that a touch of the device at a particular point will cause an inward deflection of the surface at that point. The deflection causes light to become entrapped within the surface by total internal reflection thus making it possible, by comparing the photodetector output with the CRT raster position, to determine the exact surface position of the touch.

Abstract: There is disclosed a cross-connect having a hinged rotating section panel which accepts multi-pair cables. The hinged section is mounted to a forward edge of a support section and the multi-pair cables are suspended between the two sections so that the cables remain in the same plane regardless of the position of the hinged section. The user cross connects between the cable pairs using the familiar modular plug and jack. The design of the cross-connect field is modular so that the cross-connect field can easily be added to as the system grows. The forward edge of the support panel slopes vertically to insure that the patch cords dress properly from top to bottom.

Abstract: A dual set of busses is used to provide close coupling between the data and voice services of the CS300 communication system. One of these busses is a time division multiplex bus arranged for communication between port access circuits, and the other bus is a packet-switched data processing bus used for interfacing both with the system peripherals and with the port access circuits. The port access circuits, as well as the faster peripheral circuits, can be connected to either or both busses thereby allowing for the efficient easy interchange of information.

Abstract: When using membrane key pads, it is often desirable to provide the user with a sense that contact has been made. In this regard, there is disclosed a 1 KHz 4-bit counter which is normally held at a count just beyond the place where "ones" appear in the third bit position. When it is desired to provide an audio click, the processor resets the counter to zero and then releases the counter. The "ones" in the third bit position, which occur in four consecutive counts, control the application of the 1 KHz frequency to the mechanical sounder. By connecting the fourth bit position to the synchronous reset input, the counter stops incrementing after the four consecutive "ones" and waits for the next reset by the processor.

Abstract: There is disclosed an algorithm for electronically recognizing characters. The algorithm relies upon the establishment of a particular standard "name" for each character. A name is a sequence of "u"s, "d"s, "l"s, "r"s, and "-"s that describes the path that results when the character is traversed in a particular way. The name contains a "u" when the path goes up, a "d" when it goes down and "l"s and "r"s when it goes left and right respectively. "-"s are used to retrace the path so that a (second or third) branch can be attached to an earlier point in the path. The algorithm constructs a name for an unknown character, and then, using a unique directory lookup algorithm, determines which standard name is closest to the derived name. The algorithm contains a series of rules for traversing characters to minimize ambiguities while still allowing a great deal of latitude in the recognition process.

Abstract: A memory management system is structured for use with a self-contained microprocessor to form a multi-user computer. The system operates to establish user and kernel modes each having different operating permissions. When the system is operating in the user mode, certain of the fixed functions of the microprocessor, such as interrupt-off and halt, are blocked from enablement by any user. The system is designed having multiple memory maps, some accessible when in the user mode and all accessible from the kernel mode.

Abstract: There is disclosed an ac plasma panel having gray tone and color control. The plasma panel is constructed using a matrix of discharge sites, each site associated with one or more migration sites. The migration sites, in turn, have phosphor areas in conjunction with an electrical field controlling conductor. During the ionization of the plasma gas a selective electrical field is established between a discharge site and an adjacent migration site and the electrons from the gas ionization are free to migrate to the phosphor area of the screen in accordance with the magnitude of the electrical signals on the control conductor.

Abstract: There is disclosed a processor controlled digital communication device which accepts message commands from a communication system as part of a communication protocol. These command messages are stripped from the protocol and combined within the communication device to control signaling thereat. Multi-bit time separated information (I) fields are used together with a single bit signaling (S) field. The S field bits are compiled over several frames to become the command messages.

Abstract: There is disclosed a digital telephone having dual voice and data handling capability over a single communication line. Time separated information channels are used to transport the voice and data information between the terminal and the main processor. A separate signaling channel is shared between the two information channels and information on the signaling channel is accumulated for distribution to either the voice device or the data device in accordance with address information contained within the accumulated signaling channel message.