Abstract: An electro-optical module has at least threee ports, with at least one port having an active electro-optical device for connection to electrical circuitry and at least one port having an optical port for connection to an optical fiber link. A passive coupler interfaces the various ports. The passive coupler is formed of optical fibers mounted on glass using an adhesive that exhibits refractive index-matching characteristics. The fiber-on-glass coupler is extremely small, allowing for the module to have minimal size. The coupler may be wavelength selective or wavelength insensitive. If a wavelength-selective coupler is utilized, the end surface of an optical fiber is coated with a dichroic filter to provide wavelength sensitivity. An optical fiber adapted to receive light for connection to a detector is selected to be a multi-mode fiber to increase reception of light. The remaining fibers may be single-mode fibers.

Abstract: A control method and apparatus for an electronic system having a plurality of functional elements, both intelligent and non-intelligent, interconnected by a plurality of time-division multiplexed serial data links, wherein information is normally conveyed in time slots on the data links. Control information is exchanged between the elements by using one or more of said time slots as control channels for all control information. The format of the control information is compatible with both the intelligent elements and non-intelligent elements. The control information format includes a plurality of bits for providing command data, a plurality of address bits, a valid bit to indicate that the information being transmitted is a valid message, an interrupt bit to signal a microprocessor in an intelligent device to interrupt and service the message, and a parity bit for error checking.

Abstract: An H4 byte generating algorithm is implemented by circuitry which includes counters for generating the H4 byte. The circuit is provisioned to indicate whether it is operating in a terminal multiplexer mode or an add-drop multiplexer mode. In the terminal multiplexer mode the counters are allowed to free run and continually produce successive H4 byte outputs. In the add-drop multiplexer mode selected counter outputs are compared with the received H4 byte and the number of mismatches is accumulated by a mismatch counter. When the mismatch counter reaches a predetermined number the value of the received H4 byte is loaded into the H4 byte counters and the mismatch counter is reset. Each time a proper match between H4 counter outputs and the received H4 byte is sensed, the mismatch counter is reset to 0. The presence of a red alarm will also result in the resetting of the mismatch counter and free running of the H4 byte counters.

Abstract: A line unit interface circuit used on line units in a line shelf of a digital loop carrier provides all of the logic necessary to access two subscriber lines to a line unit interface bus connected to common equipment within the line shelf. Information received from the common equipment includes signaling data, configuration data and provisioning data, which is reconfigured and processed by the line unit interface circuit for controlling the subscriber line channels. Configuration data from the common equipment is decoded to assign time slots on the line unit interface bus to the various channels serviced by the line shelf and to further provide for a timing offset between the transmit and receive strobes provided to each subscriber line circuit. A flywheel circuit is used to prevent erroneous time slot assignment in the event of noise or interference on the line unit interface bus.

Abstract: In the manufacture of optical fibers, at least a portion of a preform of optical glass is heated into a molten state and drawn to create an optical fiber of the desired diameter. To cool the fiber during the drawing process and prior to coating thereof, the invention contemplates providing a cooling device with a laminar flow of inert gas therein to surround and cool the fiber.