A centralized control unit for use in a multisystem data processing configuration to provide dynamic access to shared and non-shared peripheral subsystems is disclosed. This unit, known herein as a subsystem access unit (SAU) is able to remotely control one or more system's accessibility to peripheral subsystem's from a central location. It is able to provide this control with the capability of either allowing a peripheral subsystem to be concurrently accessed by more than one system or forcibly...

A shared memory computer method and apparatus having a plurality of sources, a memory manager, and memory units in which the memory locations of data items are randomly distributed. The memory manager includes a translation module for locating data items in the memory units and a temporary storage buffer for storing at least a portion of messages between sources and the memory units with respect to data items.

A method and apparatus for calculating charges for telephone calls in real time. The operator assistance switch connected to an originating telephone customer recognizes that a call is one which requires an immediate calculation of charges. Such calls include coin calls, calls from certain types of hotel/motel private branch exchanges, calls from customers who wish to be notified as to the amount of the charge for the call they are about to place, and calls from customers requesting a rate for a...

An optical transmission network for transmitting information between two locations is disclosed. The transmission network comprises a collection of individual two-way links with all optical sources at one end. At a first location, the outputs of at least two lasers, operating at first and second wavelengths respectively, are multiplexed together, the resulting optical power being divided between a plurality of single mode optical fiber transmission paths. Each optical transmission path may inclu...

When any one of memory cells (MC.sub.1R, MC.sub.NR and MC.sub.1L, MC.sub.NL) connected with respective bit lines (3.sub.R, 4.sub.R and 3.sub.L, 4.sub.L) is addressed, the gate potential of a transfer transistor group (7.sub.R, 8.sub.R or 7.sub.L, 8.sub.L) connected with the bit lines on the non-selected side is clamped at bit line precharge voltage, whereby the said transfer transistor group (7.sub.R, 8.sub.R or 7.sub.L, 7.sub.L) is turned off. Thus, the bit lines on the non-selected side are cu...

When a first program executed on a first processor of a plurality of processors of a multiprocessing system intends to lock a given shared resource of a main memory in order to use same, if the desired resource is in use by a second program executed on a second processor, the first processor awaits an unlock signal which indicates that one of the shared resources is released for use. The first processor responds to the unlock signal and checks whether or not the desired resource is available. If...

Apparatus for counting the number of pulses in recurring groups of pulses and for accumulating positive and negative increments in the number of pulses in each group in excess of a predetermined amount. The pulse groups are applied to an UP (forward) counter which overflows into a preset DOWN (backward) counter to provide a signal for incrementing a bidirectional counter. The number appearing in the bidirectional counter after a preceding pulse group is preset into the DOWN counter between group...

A telephone switching system which comprises a program controlled main processor and a wired logic input-output arrangement for collecting and registering input information obtained from the lines and trunks served by the system and for transmitting control signals on the trunks and data to other controlled output units. The processor includes a timing arrangement which defines short repetitive time cycles (each cycle is 1.251 milliseconds long). During a first fixed portion of each time cycle t...

A data communication system, including at least one base station and at least one portable module 120, wherein the portable module 120 transmits data on a high frequency, and the base station transmits data on a much lower frequency. Transmissions by the base station use a pulse-width modulation scheme where the most commonly used signals correspond to the shortest pulse. A "read" command is encoded as the same pulse width as one of the two write commands. Since the direction of data transmissio...

A voltage regulator for an electrical generator driven by an internal combustion engine is cooled by water flowing through a heat exchanger attached to the voltage regulator. The cooling water is obtained from the upstream side of a secondary cooling loop of water-to-water cooling system associated with the internal combustion engine, such secondary water typically at an ambient temperature less than or equal to that of the air. In one embodiment, the heat exchanger is formed from a heat conduct...