Multichannel alignment system and method

• US 5,621,720 A
• Filed: 02/14/1996
• Issued: 04/15/1997
• Est. Priority Date: 04/02/1992
• Status: Expired due to Term

• Current Assignee: Applied Digital Access, Inc. (Lumentum Holdings Inc.)
• Original Assignee: Applied Digital Access, Inc. (Lumentum Holdings Inc.)
• Inventors: Bronte, Jeffery S., Lever, Mark J., Hartmann, Paul R., Pope, Kevin T.
• Primary Examiner(s): BLUM, RUSSELL
• Application Number:
  US08/601,264
• Time in Patent Office: 426 Days
• Field of Search: 370/13, 370/16, 370/16.1, 370/100.1, 370/105.1, 370/105.2, 370/105.4, 371/20.1, 379/1, 379/10
• US Class Current: 370/241
• CPC Class Codes: H04J 3/0608 Detectors therefor, e.g. correlators, state machines
• CPC Class Codes: H04J 3/0623 Synchronous multiplexing systems, e.g. synchronous digital hierarchy/synchronous optical network (SDH/SONET), synchronisation with a pointer process
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085
• CPC Class Codes: H04M 3/22 Arrangements for supervision, monitoring or testing
• CPC Class Codes: H04M 3/244 for multiplex systems

Abstract

A DS3 level access, monitor and test system for a telephone network. The system provides selective, and hitless, bit overwrite in any of the embedded DS1, DS0 and subrate channels in a DS3 signal. Multiple DS0 and subrate channels can be tested via the asynchronous time slot interchange in conjunction with the recombiner of the present invention. A second embodiment of the invention partitions the system into a base subsystem, a communications link and a remote subsystem, collectively referred to as a distributed architecture system. The distributed architecture system provides all of the performance monitoring and testing capabilities of the existing access system. The distributed architecture system provides a mechanism to transport a plurality of asynchronous and rate independent signals across the link to permit remote testing of digital and voice DS0 frequency circuits. In the preferred embodiment, the link that connects the base to the remote system is a standard DS1 channel. The clocks for the transmit and receive paths are derived from the same source, thus providing a common reference clock to both ends of the link. At the remote site, the channels undergoing test are embedded DS0 channels within a DS3 signal accessed through a DS3 interface at the base site.

Claims

1. A multichannel alignment system, comprising:

a first channel access subsystem that provides a first round-trip, rate-controlled, flame-aligned channel;

a second channel access subsystem that provides a second round-trip, rate-controlled, flame-aligned channel;

a test resource transceivably connected to each of the channel access subsystems; and

an alignment software program executed on the test resource that aligns the first channel with the second channel, wherein the program drops data from one of the channels until the other channel is aligned.

2. The system defined in claim 1, additionally comprising a system controller that provides a pattern for both channels.

3. The system defined in claim 1, wherein the first channel transports a DS0 signal.

4. The system defined in claim 3, wherein the pattern is at a DS0 level.

5. A method of aligning a first channel with a second channel in a system having a test resource, the method comprising the steps of:

providing a test pattern for the first channel and the second channel;

sampling the pattern on the first channel and on the second channel;

synchronizing the first channel to the pattern;

synchronizing the second channel to the pattern;

determining the difference in alignment in a number of bytes received between the two channels; and

dropping the difference in number of bytes from the channel that is ahead of the other channel, thereby aligning the pattern on the channels.

6. The method defined in claim 5, wherein the first channel transports a DS0 signal.

7. The method defined in claim 5, wherein the test pattern is at a DS0 level.

8. The method defined in claim 5, wherein the test pattern is selected by a controller.