Abstract: A fiber-based digital loop carrier (DLC) system provides multiplexed optical transport for telephone line circuits between a terminal in a central office and a remote terminal. The remote terminal performs the multiplexing and demultiplexing for interfacing channels on the fiber(s) to individual subscriber line circuits. To expand the capacity of DLC systems to carry broadband services, fibers are run from broadband terminations in the central office to the remote terminal. The remote terminal includes interfaces for coupling to optical fibers, for two-way telephone communications and for broadband communications. This terminal also includes a line card rack, for mounting various line cards and providing appropriate connections of the cards to the channels through the fiber interfaces. Some of the line cards provide normal telephone type service connections for one or more telephone lines.
Abstract: The present invention involves a transmission of a known signal over a line intended for a digital subscriber line (xDSL) service, measurement of a resulting waveform received through the line and processing of the received signal to derive a set of eigenvalues characterizing the transfer function of the line. In the preferred embodiment, a transmitter applies a known test signal waveform to the transmission line. The test signal corresponds to a desired one of several available xDSL services. At the receiving end of the line, the output signal from the line is sampled, to capture a digitized sample waveform for the received signal. A computer processes the captured waveform to determine eigenvalues characterizing the transfer function of the line with respect to the one service. If the eignevalues for the line bear predetermined relationships to threshold values, indicating acceptable line transfer function for the desired xDSL service, then the invention certifies the tested line for use on that service.
Type:
Grant
Filed:
September 12, 2000
Date of Patent:
November 5, 2002
Assignee:
Verizon Services Group
Inventors:
Allan Schneider, Frederick G. Hofman, James Everett Sylvester