At&t Bell Laboratories

At&t Information Systems Inc.

At+t Corp.

American Telephone and Telegraph, Co.

John S Helton

Scott E Farleigh

Stephen R Peck

Allen L Larson

Gary J Grimes

Dwight W Kohs

Floyd Craig Wolverton

William K Honea

Edward J Bortolini

Hung-San Chen

Frank C Liu

An apparatus that provides two different sources for generating the bytes to be inserted into frames of data being communicated through a switching unit. This apparatus allows for the insertion of variable, programmable data patterns in multiple frames. Under program control of a controller, the first source can selectively write data into designated time slots within designated rows and designated frames of multiple frames. Different data can be inserted into different rows of the same column of each frame. In addition, different data for different frames can be inserted into different rows of the same column. Also, the same data can be inserted into designated a row and column of a designated frame. The second source can write data into every row of a designated column of every frame.

Apparatus for insertion of overhead protocol data into a switched data

A duplicated transmission system in which two optical wavelengths are utilized on each of a pair of optical links with one optical wavelength communicating data and the other optical wavelength communicating a signal designating an active optical link of the pair. Each of the optical links is terminated on a transmit unit and a receive unit. The two transmit units determine which of the optical links is the active optical link, and each of the transmit units then transmits a signal on the second wavelength of the terminated optical link indicating this decision. The second wavelength of the active optical link designates that it is active, and the second wavelength of the standby optical link designates that it is the standby optical link. Upon reception of the information on the second wavelengths, the receive units both select the active optical link.

Selection of transmission facilities using optical wavelength division

A broadband ISDN communication system (10) comprises a plurality of bit-serial synchronous time-division multiplexed ring networks (15) interconnected by a circuit switch (11). In each network, terminal equipment (14) is interfaced to a fiber-optic ring bus (12) by add/drop multiplexers (13). Single time slots (201) on the ring function as independently-assignable channels. Each time slot carries one bit at an 8 Kbps rate. Ring bandwidth is 45 Mbps. The circuit switch is a time-division multiplexed time-space switch. The time stage (301) comprises a plurality of time slot interchangers (TSI 303), one for each switch output port (306). Each TSI unit is connected to all switch input ports (305) and through the space stage to its corresponding output port. The space stage (302) is a time-multiplexed space stage. The switch is fully non-blocking and has broadcast capability. System bandwidth is dynamically allocated to users in single time slot (8 Kbps) increments, under control of a network manager (16).

Broadband multirate switching architecture

The subject wideband switching network provides inexpensive point-to-point wideband communication connections. Wideband source and destination terminal equipment are either connected to modems which encode the analog signals used by the wideband source terminal equipment into digital signals for transmission through the wideband switching network and decode the received digital signals into analog signals used by the wideband destination terminal equipment; or are directly connected to the wideband switching network if source and destination terminal equipment transmit and receive digital signals. The modems are connected to the wideband switching network by optical fibers. The wideband switching network is a point-to-point space division switch that is comprised of a matrix of high frequency semiconductor crosspoints. Wideband communication connections are originated by a subscriber transmitting connection control signals to the wideband switching network controller on a dial-up basis from a telephone station set, on a data link from a computer or directly from a keyboard associated with the wideband switching network controller. The wideband switching network can concurrently switch any combination of voice, audio, video, data.

Wideband switching system

A control circuit for receiving clock signals from duplicated sources, such as a pair of Time Slot Interchanges (TSI) and for normally extending the clock signal of the on-line source to clock signal utilization devices, such as digital port boards. The control circuit contains circuitry which ensures that no spurious pulses are applied to the port boards when the TSIs interchange their on-line/off-line status.

Glitchless clock signal control circuit for a duplicated system

Growing community of inventors

Louisville, CO, United States of America

John S Helton