Abstract: An optical device is disclosed which provides wavelength multiplexing/demultiplexing utilizing a plurality of focusing Bragg reflectors. Each Bragg reflector includes a plurality of confocal (i.e., common foci) elliptical grating lines, with the exit/entrance ports of the input/output waveguides located at the foci of the ellipse. By virtue of the elliptical design, the signal propagating outward from the exit port of the input waveguide will be reflected by the appropriate Bragg reflector and focused into the entrance port of the appropriate output waveguide. When each Bragg reflector exhibits a different ellipticity, but shares one common focal point, optical multiplexing/demultiplexing may be achieved. Optical filtering may be achieved when all Bragg reflectors are designed to have common foci.

Abstract: In a private telecommunications network, a plurality of digital PBXs are interconnected via pairs of codecs. The codecs of each pair, or "tandem", are each operative to encode 64 kilobit/second (kbps) mu-law speech so as to compress it to 16 kbps speech for transmission to the other codec in the tandem. The latter is operative to thereafter decompress the 16 kbps speech back to 64 kbps. Each codec has a second mode of operation in which, rather than decode the encoded speech, it preserves the bits thereof in its own output signal. The codec transitions to this mode whenever it recognizes the presence of another codec on its high-bit-rate side of the connection. As a result, only one encoding/decoding cycle is performed across the connection, thereby minimizing the speech-coding-induced distortion and delay therein.

Abstract: In a vertical gradient freeze (VGF) process for growing a large crystal of a Group III-V compound semiconductor in a pyrolytic boron nitride crucible (11), a major part of the inner surface of the crucible is first oxidized to form a boric oxide layer (12).

Abstract: In a telephone local loop transmission arrangement, data is communicated from the customer premises to the central office utilizing a multi-dimensional, passband signal illustratively at 480 kb/s and 1.544 Mb/s.

Abstract: A method and apparatus for optimizing resource allocations is disclosed which utilizes the Karmarkar algorithm to proceed in the interior of the solution space polytope. The values of the allocation variables are limited by upper and lower bounds, either individually or collectively with the same common bound. Each successive approximation of the solution point, and the polytope, are normalized such that the solution point is at the center of the normalized polytope using a diagonal matrix of the current solution point. The objective function is then projected into the normalized space and the next step is taken in the interior of the polytope, in the direction of steepest-descent of the objective function gradient and of such a magnitude as to remain within the interior of the polytope. The process is repeated until the optimum solution is closely approximated.

Abstract: An etching process is described for etching aluminum containing III-V semiconductor compounds. The etch solution contains dichromate ion in acid aqueous solution in which the acid is either phosphoric acid or sulfuric acid. The etch solution is highly selective in that it etches the aluminum containing III-V semiconductor compounds without etching significantly other III-V semiconductor compounds not containing aluminum exposed to the same etching solution. the etching process is extremely useful in fabricating a variety of III-V semiconductor devices including heterojunction bipolar transistors, heterojunction field effect transistors and self-enhanced electro optic devices.

Abstract: A method for lithographic alignment utilized in the manufacture of integrated circuits is described. The procedure includes an initial calibration through the lens system to expose a calibration material in a diffraction grating pattern. An interference pattern is produced above the grating with intersecting laser beams. By adjusting the path and/or phase of these beams the interference pattern is aligned with the diffraction pattern to establish a calibration point corresponding to a reference intensity in the intensity of the diffracted light. A wafer to be exposed is then placed in the exposure tool and is aligned by observing the diffraction pattern from a diffraction grating fiducial mark induced by the calibrated interference pattern.

Abstract: An emergency call service system, such as an E911 system, provides service system personnel with the addresses of abandoned calls to facilitate abandoned call follow-up. When a call comes in to a "911" ANI controller (21), the calling number is recorded. If the call is abandoned prior to being assigned by ACD 23 to an agent position (27-28) for being answered, an abandoned call ALI function (25) is invoked to obtain information pertaining to the calling number from a database (20), similarly to a non-abandoned call. When obtained, the information is displayed on equipment (29) such as a printer, terminal, or PC, to make it available to system personnel for use in following up on the call. The ANI controller serves both "911" emergency calls and emergency call-handling agents as well as other calls and other users, by switching the emergency calls to the agents and switching the other calls to the other users.

Abstract: An electrical interconnection medium is made as a composite of electrically conducting, magnetic particles in a nonconductive matrix material. Particles are magnetically aligned into a network which extends in at least two dimensions as, e.g., in a sheet or layer medium. A layer medium may further include additional, larger conductive particles which may be magnetically aligned into columns extending the thickness of the medium; typically, in this case, the medium serves as an anisotropically conductive medium in the direction of the columns, with slight in-plane conductivity imparted by the network aiding the dissipation of electrostatic charge.

Abstract: A new class of silicon compounds having a high percentage of silicon atoms bonded to three other silicon atoms has been synthesized. These materials denominated polysilynes form smooth amorphous films which have quite useful properties. For example, photooxidation produces a refractive index change from 1.70 to 1.45. Similarly, photooxidation also produces a substantial change in solubility. Thus the materials are useful for the fabrication of optical and electronic devices.

Abstract: This invention relates to an arrangement for efficiently transmitting facsimile signals from a facsimile source to a facsimile destination using a standard facsimile user interface. The connected switched communications network recognizes that the call is from a facsimile source or to a facsimile destination and causes the facsimile signals to be transmitted at the transmission speed of the source to storage in a network. Subsequently, the signals are transmitted from storage to a facsimile destination at the transmission speed of the destination when the destination becomes available. Advantageously, the source need not wait for the destination to become available before transmitting, and the transmission can take place at a bit rate that matches the source and the destination even when these bit rates are different. Retransmission because of errors in one link is only required for that link, i.e., from the source to the storage or from the storage to the destination.

Abstract: A method and apparatus for operating a lottery system. Customers purchase lottery entries using their customer stations to send lottery entry data to a toll switching system equipped to prompt customers and accept lottery entries. Customer identification data for identifying purchasers is transmitted to that toll switching system in the form of automatic number identification signals from switching systems connected to the customers and personal identification codes keyed by customers. Lottery data is stored in the toll switching system and transmitted to a centralized lottery data base system for determining lottery winners. Advantageously, customers may purchase entries in existing, periodic draw lotteries from their own customer stations, using the shared facilities, and the high peak capacity for handling lottery traffic of a public switched network.

Abstract: A data hashing arrangement particularly suitable for efficient database storage and fast retrieval of large numbers of character strings. A database address is determined for a character string by replacing individual characters with random numbers selected from a predefined table of random numbers. The table locations of the selected random numbers are uniquely defined by the characters. The selected numbers are combined by iteractive bit reordering and exclusive-OR operations to form a result, which is then used to derive the database address where the character string is stored.

Abstract: A personal data card (10), comprised of a semiconductor chip (28), sealed by encapsulant (38) in an opening (26) in a body (12), is advantageously provided with a shock absorbing device (38) which substantially circumscribes the encapsulant to substantially isolate the encapsulant from the body of the card. By isolating the encapsulant from the card body, the shock absorbing device reduces the stresses transmitted from the card body into the capsulant and into the chip when the card is flexed. In this way the incidence of cracking of the chip caused by the stresses generated upon flexing of the card is reduced.

Abstract: A communication station capable of transmitting audible speech represented by speech signals received on the line during the on-hook state. A calling party name may be spoken at the station without requiring the call to be answered. The station is also usable, while on-hook, for receiving voice messages, e.g., emergency warnings, transmitted from a central office or customer premises switch.

Abstract: A multilayer ceramic package is disclosed which includes a high frequency interconnect that simulates the performance of a conventional coaxial connector. The interconnect comprises a signal conductor surrounded by the ceramic material forming the package. A plurality of vias are formed through the ceramic material so as to surround the conductor. These vias are then connected to a ground plane to form the outer shielding for the high frequency interconnect.

Abstract: An analog to digital interface circuit includes two matched, symmetrical, differential amplifiers which in response to an analog signal having a rising edge and a falling edge produce first and second output signals which are identical but 180.degree. out of phase; whereby the rising edge of the analog signal corresponds to the rising edge of the first output signal, the falling edge of the analog signal corresponds to the rising edge of the second output signal and the time interval between the rising edges of the two output signals is equal to the time interval between the rising and falling edges of the analog signal. The outputs of the differential amplifiers are further processed by two matched, symmetrical buffers which produce first and second digital signals having like falling edges corresponding to the rising and falling edges of the analog signal, respectively.

Abstract: A high capacity metropolitan area network (MAN) is described. Data traffic from users is connected to data concentrators at the edge of the network, and is transmitted over fiber optic data links to a hub where the data is switched. The hub includes a plurality of data switching modules, each having a control means, and each connected to a distributed control space division switch. Advantageously, the data switching modules, whose inputs are connected to the concentrators, perform all checking and routing functions, while the 1024.times.1024 maaximum size space division switch, whose outputs are connected to the concentrators, provides a large fan-out distribution network for reaching many concentrators from each data switching module.

Abstract: A gate electrode having an insulating top layer as well as insulating sidewall spacers permits the source and drain regions to be electrically contacted through windows directly above the source and drain regions formed in a window pad layer. There is a conducting layer, termed a window pad layer, over portions of these regions. Because of the insulating top layer and sidewall spacers on the gate, the window may be misaligned with respect to the source and drain regions, and maybe even closer to the gate than are these regions, but electrical contacts to these regions are still obtained. The window pad layer may also be used as sublevel interconnect.