Abstract: A loss-less, optical add/drop multiplexer according to the present invention includes a rare earth-doped fiber amplifier integrated with a wavelength-selective fiber path coupled between two directional optical transfer devices for selectively adding and dropping optical signals from a multi-wavelength signal, such as a wavelength division multiplexed optical signal. One or more fiber gratings are disposed along the length of the rare earth-doped fiber amplifier or between segments of the rare earth-doped fiber so that at least one grating is used for reflecting each optical signal that is expected to be added to or dropped from the multi-wavelength optical signal. By using this configuration, appropriate amplification is provided to compensate for losses in the add, drop, and through paths.

Abstract: A telephone instrument is disclosed which includes a swivel visual display module overcome by employing a telephone base having upper and lower housings. A swivel visual display module is pivotally mounted and supported by pivot points in both the upper and lower base housings. At least one cantilever snap member is molded into one of the base housings, for example, the upper base housing, and is employed to engage indents molded into an outer convex surface of the visual display module to hold the visual display module in several angular positions. Additionally, the at least one cantilever snap member is employed to engage a lower edge of the visual display module and in conjunction with stop members on the visual display module to secure the visual display module in a full upright position.

Abstract: A network element with a centralized switch fabric is able to support multiple switching functions while meeting established performance requirements by using a control system based on an embedded signal status protocol. Generally, each input signal within a transmission path is monitored to derive signal status information, which is then individually encoded and embedded within the input signal. The embedded signal status can be decoded and provided as input to control logic for processing at any point within the transmission path, as necessary. In the case of a centralized switch fabric, the control logic resolves an address of a single input signal based on the embedded signal status and provides this resolved address to the switch fabric so that the appropriate input signal can be selected. In the present invention, the control logic may be configured to support any given application, e.g.

Abstract: An optical switch includes an optical router portion for distributing multi-wavelength optical signals received at input ports of the switch, an optical combiner portion for supplying multi-wavelength signals at the output ports of the switch, and optical fibers for interconnecting the optical router portion and optical combiner portion. Selected ones of the interconnecting optical fibers include wavelength-selective elements, such as fiber gratings, which are capable of transmitting or reflecting individual channels within the multi-wavelength optical signal so that a selected channel of a particular wavelength can be routed from any of the input ports to any of the output ports of the switch. In one exemplary embodiment, the optical router portion includes a plurality of input optical couplers, wherein each input optical coupler is associated with a corresponding input port of the optical switch.

Abstract: An optical line protection switching system is realized by employing a plurality of rare earth-doped fiber optical amplifiers as gain-switched optical connections, for example gain-switched optical distributors, i.e., commutators, and/or gain-switched optical selectors in a gain switched optical line protection switching system. In one embodiment, at least one or more gain switched optical distributors are employed to realize so-called head-end switching of an incoming optical signal and one or more gain switched optical selectors are employed to realize so-called tail-end switching of the optical signal to form a 1.times.1 (1.times.N) optical line protection switching system. In another embodiment, an incoming optical signal is bridged to one or more optical paths, while the tail-end switching is realized by employing one or more gain-switched optical selectors to form a 1+1 (1+N) optical line protection switching system.

Abstract: The problem of tracking rapid changes in the echo signals associated with modems is eliminated by using an echo canceler consisting of cascaded adaptive filters. Each filter in the structure contributes to the modeling of the overall echo path impulse response, with a longer filter providing the ability to model long echo path impulse responses and a shorter filter providing the ability to track changes in the echo path impulse response over time.

Abstract: The subject matter is directed to a parallel array of optical amplifiers and is also directed to equally sharing the optical power supplied by a plurality of optical pumps among the array of optical amplifiers such that if one of the pumps fails the power outputted by the remaining pumps is still equally shared among the array of optical amplifiers.

Abstract: A protection assembly for connectors is included on a circuit pack to prevent damage caused when a connector is removed while signal power is still being supplied to the circuit pack. More specifically, the protection assembly is disposed on the front side of the circuit pack to prevent access to the connector until signal power is automatically cut off from the circuit pack. In one embodiment, the circuit pack is the type having a lever arrangement capable of causing the circuit pack to engage and disengage the backplane of an equipment frame. When the circuit pack is engaged in the backplane, signal power is supplied through the connector that is accessible, for example, on the face plate of the circuit pack. The protection assembly includes a first shield member mounted on the face plate of the circuit pack in a location adjacent to the connector. The protection assembly further includes a second shield member mounted or otherwise formed on the lever arrangement.

Abstract: A gain-switched optical selector is realized by employing an optical rare earth-doped fiber optical amplifier as the switching element per se. Each of the optical rare earth-doped optical amplifiers acts as an ON/OFF switch. Also, the gain-switched optical selector of this invention is a natural fit into today's optically amplified optical communication systems. In one embodiment, this is realized by employing a pump select circuit in conjunction with a plurality of pumps and a plurality of corresponding rare earth-doped fiber optical amplifiers. The particular pump and corresponding optical amplifier are selected by use of a monitor arrangement to determine which signal is to be selected and routed to an output. In another embodiment, a so-called tuned pump arrangement is employed in conjunction with a plurality of filters and a corresponding plurality of rare earth-doped fiber optical amplifiers.

Abstract: An apparatus is provided for adding a dither signal to an optical carrier modulated with an information signal. The apparatus includes a dithering element having an input and an output in series with an optical carrier modulated with an information signal. A differential element having an inverting input, a non-inverting input, and an output is coupled to the input of the dithering element. A signal generator, which is provided for producing a desired dither signal to be added to the modulated optical carrier, is coupled to the non-inverting input of the differential element. A feedback element produces a signal related to the output of the dithering element and couples the signal related to the output of the dithering element to the inverting input of the differential element.

Abstract: An optical line protection switching system is realized by employing a plurality of rare earth-doped fiber optical amplifiers as gain-switched optical connections, for example gain-switched optical distributors, i.e., commutators, and/or gain-switched optical selectors in a gain switched optical line protection switching system. In one embodiment, at least one or more gain switched optical distributors are employed to realize so-called head-end switching of an incoming optical signal and one or more gain switched optical selectors are employed to realize so-called tail-end switching of the optical signal to form a 1.times.1 (1.times.N) optical line protection switching system. In another embodiment, an incoming optical signal is bridged to one or more optical paths, while the tail-end switching is realized by employing one or more gain-switched optical selectors to form a 1+1 (1+N) optical line protection switching system.

Abstract: A facility for mapping a plurality of different Virtual Circuit Channels (VCC) into a single VCC is provided for use in a data network. In operation, the facility assembles, in turn, data cells each having a data payload and appropriate header identifying a respective VCC into a series of data cells. The series is then segmented into a predetermined number of data payloads, and a header identifying a common connection over the network is then appended to each of the payloads. The result is then transported over the data network via the common connection.

Abstract: The propagation of very high frequency signals, e.g., 8 to 10 GHz, via a path printed on a printed wiring board is enhanced by arranging the path so that it simulates a high-quality transmission path at very high frequencies. The path comprises a conventional lead and a series of microstrips, in which the design of the microstrips is optimized to (a) minimize insertion loss and group delay distortion, (b) maximize return loss, and (c) minimize pulse distortion.

Abstract: A telephone base includes a base module and a rotatable base stand module. The base module may be elevated to a plurality of inclined positions by employing in the base stand modules the plurality of cantilever snap members each of which has a protruding locking member. The telephone base module includes a plurality of locking apertures which correspond to the locking members on the cantilever snap members. The desired inclined positions are obtained by rotating the base module around pivot elements in the base stand module and inserting the locking members on the cantilever snap members into appropriate ones of the locking apertures in the base module. Additionally, the base stand module may be rotated and locked in place to the base module by additional locking members to orient the telephone base for wall mounting. Advantageously all the elements required for the above features are integrally molded into the base module and the base stand module.

Abstract: A gain-switched optical distributor, i.e., commutator, is realized by employing an optical rare earth-doped fiber optical amplifier as the switching element per se. Each of the optical rare earth-doped fiber optical amplifiers acts as an ON/OFF switch. Also, the gain-switched optical distributor of this invention is a natural fit into today's optically amplified optical communication systems. In one embodiment, this is realized by employing a pump select circuit in conjunction with a plurality of pumps and a plurality of corresponding rare earth-doped fiber optical amplifiers. The particular pump and corresponding amplifier is selected by use of a monitor arrangement to determine which signal is to be selected and routed to an output. In another embodiment, a so-called tuned pump arrangement is employed in conjunction with a plurality of filters and a corresponding plurality of rare earth-doped fiber optical amplifiers.

Abstract: The problem of tracking rapid changes in the echo signals associated with modems is eliminated by using an echo canceler consisting of cascaded adaptive filters. Each filter in the structure contributes to the modeling of the overall echo path impulse response, with a longer filter providing the ability to model long echo path impulse responses and a shorter filter providing the ability to track changes in the echo path impulse response over time.

Abstract: An apparatus is provided for adding a dither signal to an optical carrier modulated with an information signal. The apparatus includes a dithering element having an input and an output in series with an optical carrier modulated with an information signal. A differential element having an inverting input, a non-inverting input, and an output is coupled to the input of the dithering element. A signal generator, which is provided for producing a desired dither signal to be added to the modulated optical carrier, is coupled to the non-inverting input of the differential element. A feedback element produces a signal related to the output of the dithering element and couples the signal related to the output of the dithering element to the inverting input of the differential element.

Abstract: Provisioning a Central Office (CO) Basic Rate Interface (BRI) access is a complex procedure which involves hundreds, and potentially thousands, of parameters that must be asserted to configure the CO for a particular users service profile. In such a complex procedure, errors in the provisioning may be introduced which are difficult and costly to detect and correct. To solve this problem, a provisioning tool which exercises BRI lines i.e., digital subscriber lines (DSLs) from a CO to a premises switch is defined which validates that transport related restrictions and permissions are properly administered at the CO. This is achieved by the system calling itself over such lines, and varying the types (e.g., voice, digital, data, 3.1 kHz audio, et al.) of call attempts that are placed to ensure that all lines support the intended services.