Reliance Comm/tec Corporation

Marconi Communications Gmbh

Tellabs Beford, Inc.

Joseph L Whitehead

Mahlon Danny Kimbrough

Barry Joe Ethridge

Philip L Dillon

James Joseph Gainer

A technique for multiplexing high speed computed data with digitized voice signals onto a fiber optic cable for transfer to a local central office. The data packets of a number of computers are networked by way of a distributed hub that extends to residences, offices, apartments, etc. The data packets are switched outside the switching fabric of a local central office and routed to the internet or elsewhere. Command signals that are for accessing the internet are transmitted and received as 10 MHz Ethernet data packets on the distributed hub.

Distributed ethernet hub

A clock synchronization scheme for synchronizing a remote terminal to a distantly located central office terminal. In order to obtain synchronization, the central office terminal repetitively transmits a frame which has in it only one synchronization bit located in a predetermined position. The remote terminal includes a voltage connected oscillator whose output is used to determine when the predetermined bit position should be received from the central office terminal. The remote terminal controls the frequency of the oscillator based on the phase and frequency difference between the actual received synchronization bit and the bit position that the terminal says that bit should be received in. Once synchronization is achieved, the central office terminal transmits in each frame a three bit window which includes the synchronization bit. The remote terminal then searches each frame for the three bit window as long as synchronization is maintained.

Clock synchronization scheme for digital transmission

An amplifier for use with low level pulse code modulation (PCM) nonreturn-to-zero (NRZ) signals. The amplifier has a high, but controllable gain and does not have a DC shift at its output as long as there is at least one zero or one one bit in each of frame PCM NRZ signals. The amplifier includes a feedback circuit to control the bias of one of the two stages of amplification when zeroes are being received. The amplifier also includes an AGC circuit which reduces the gain when a high amplitude one is received.

High gain amplifier for reception of low level pulse code modulation

A circuit for the non-linear limiting of the metallic current flowing in telephone line conductors. The circuit senses the metallic current flowing in the conductors. If that current exceeds a predetermined limit, the circuit provides from a controlled and variable voltage source a voltage across the conductors whose amplitude is reduced from the essentially constant amplitude voltage provided across the conductors when the current does not exceed the limit. The reduction in voltage amplitude is sufficient to maintain the metallic current at the limit.

Metallic current limiter

An oscillator for generating a master clock frequency and also dividing that frequency by two. The oscillator uses one flip-flop of a dual D package as the generator for the master clock frequency and the other flip-flop in that package to divide that frequency by two.

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Decatur, TX, United States of America

Joseph L Whitehead