Abstract: A stabilizing agent for a hydroalkoxysilane such as triethoxysilane and trimethoxysilane characterized by comprising a carboxylate such as an alkali metal salt or an alkali earth metal salt of a carboxylic acid having 1 to 18 carbon atoms; a method for stabilizing a hydroalkoxysilane by combining it with a carboxylate; and a hydroalkoxysilane stabilized with a carboxylate.

Abstract: In an optical telecommunications system using wave division multiplexing (WDM) a wavelength add-drop multiplexer (WADM) has an array of adjacently connected filters, each for selecting light of a respective wavelength being transmitted in a multiplexed data stream along an optical fibre, each of the array of filters being adjacently connected to a portion of the array which is a nominally transparent filter and having means for moving the array so that movement between filters in use occurs via the nominally transparent filter portion of the array. Further, in a method of operating a WADM the transition between two filters of an array of filters each for selecting light of a respective wavelength being transmitted in a multiplexed data stream along an optical fibre occurs by way of a nominally transparent filter portion of the array.

Abstract: Data is protected in a data transmission system operating on the synchronous digital hierarchy. The data is transmitted in multiplex form between ports in the system and protection is applied between ports at different or the same aggregate bit rates. This protection is achieved by selecting between individual portions of the payload within the aggregate signals and each part of mutually protective portions has the same nominal traffic capacity. By duplexing an alternative signal path is created to ensure a continuity of traffic through the system in the event of a fault in one path.

Abstract: A process for the production of monosilanes from the high-boiling residue resulting from the reaction of organohalides with silicon metalloid in a process typically referred to as the "direct process." The present process comprises forming a mixture comprising an organotrihalosilane and the high-boiling residue in the presence of hydrogen gas and a catalytic amount of aluminum trichloride. The present process results in consumption of the organotrihalosilane rather than a net increase which typically occurs in processes for hydrogenation of the high-boiling residue. At least a portion of the catalytic amount of aluminum trichloride may be formed in situ during conduct of the direct process and isolation of the high-boiling residue.

Abstract: A data transmission system in which multiplex data is created in accordance with the Synchronous Digital Hierarchy standard includes an add-drop multiplex having a switch across which data streams are switched between a pair of multiplexers and each input and output for a stream has a rejustifier circuit the timing of which is extracted from a timing extract from the other side of the switch.

Abstract: An add/drop multiplex includes a matrix switch, the drop side of which is connected via buses to respective time slot assignment function circuits which are interconnected by at least one bus capable of transferring traffic between the add and the drop functions of the multiplex.

Abstract: A digital communications apparatus for receiving a plurality of parallel digital input signals (IN1 . . . IN1 6) all at one rate, and for interleaving multiple bit sequences of a predetermined length from each of the input data streams into a single data stream at a higher rate. The apparatus has a plurality of first stage blocks (BIC1) each adapted to receive a plurality of the input data streams and to output a similar number of data streams at the same bit rate but with the bits of the incoming data signals interchanged. The first stage blocks are connected to a plurality of second stage blocks (BIC2) each connected to said first stage blocks (BIC1) in such a manner that each secondary stage block is connected to a first stage block by a single data stream so that the secondary stage blocks (BIC2) interchange the bits of the already bit-interchanged input signal to generate a plurality of digital output data streams.

Abstract: A transmission system in which a plurality of data streams are to be multiplexed and sent between receiving and transmitting equipment. At the transmit end the system comprises a plurality of worker tributary cards (51, 52) each having an input port (57) connected to an individual tributary to be sent to an associated multiplexer, and a stand-by tributary card (56) operative to replace a failed worker card. All the worker tributary cards (51-55) are interconnected by a common line (60) leading to the iput port (57) of the stand-by tributary card (56) but in normal operation being isolated from said line by a controllable unity-gain buffer 58.

Abstract: A system for transmitting digital data by time division multiplex (TDM) includes a transmission terminal for transmitting a TDM data stream having a frame structure which includes fixed stuff bytes and/or frame overheads forming part of the payload but not normally available to the user. The system includes a processor for locating said fixed stuff bytes, and overwriting at least some of the fixed stuff bytes to introduce mark parity, and a receive terminal having a processor for detecting the introduced parity bytes and determining whether or not there has been an error in transmission. The processor at the receive terminal includes an AND-gate to which the transmitted TDM signal containing mark parity is fed, a clock for supplying a clock signal to the AND-date, a bistable flip-flop connected to the output of the AND-gate, and a band pass filter for filtering the output of the AND-gate.

Abstract: A terminal for a telephone system and for receiving digital data in the form of a time multiplexed (TDM) data stream incorporating frames appearing at a predetermined frame period and each frame incorporating a frame word. The terminal comprises a frame word detecting circuit (52) for detecting frame words; an alignment detecting circuit (53, 55, 56) for determining whether a received TDM data stream is in alignment or not; a search circuit (53, 55, 56, 57, 59, 60) for initiating a bit-by-bit search of the incoming data stream for the sequence of bits forming the frame word when an "out-of-alignment " condition has been detected by the said alignment detecting circuit; and a delay circuit (58) for delaying the start of the bit-by-bit search after an "out-of-alignment" condition has been detected.