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MEANS OF DETERMINING SPEED CAPABILITIES OF A CONNECTION BASED UPON THE CAPABILITIES OF THE CONNECTED NODES AND MEASUREMENTS OF THE CONNECTING MEDIUM

IP.com Disclosure Number: IPCOM000021400D
Original Publication Date: 2000-Nov-01
Included in the Prior Art Database: 2004-Jan-16
Document File: 1 page(s) / 21K

Publishing Venue

Sony Technical Digest

Related People

David V. James: INVENTOR [+2]

Abstract

This invention was primarily developed for ILink products, particularly long distance links. It determines the speed capabilities of a link by measuring its in-use error rate. The method of measuring a link's in-use error rate is a more reliable speed-measuring method than relying on vendor-specified speeds. Though this invention was developed for IEEE Std 1394 Serial Bus, it could be applicable to other links as well.

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Sony Technical Digest, Volume 3, November 2000, ISSN 1521-5180

MEANS OF DETERMINING SPEED CAPABILITIES OF A CONNECTION BASED UPON THE CAPABILITIES OF THE CONNECTED NODES AND MEASUREMENTS OF THE CONNECTING MEDIUM

Invention by: David V. James

Glen Stone

This invention was primarily developed for ILink products, particularly long distance links. It determines the speed capabilities of a link by measuring its in-use error rate. The method of measuring a link's in-use error rate is a more reliable speed-measuring method than relying on vendor-specified speeds. Though this invention was developed for IEEE Std 1394 Serial Bus, it could be applicable to other links as well.

This invention seeks to solve the problem created by the dependence that the useful speed of a connection has on the type of cable that is connected. For example, the longer distance POF may have to operate at a slower speed, due to optical dispersion. Also, the speed capabilities of a short cable may depend on how the connector was attached. This invention seeks to remedy the cable-dependence problem by accurately reflecting actual operating conditions through measuring the capability of the link via error rates.

Each connector type has a default base rate. For copper cables, each cable plug identifies its maximum operational speed, above which EMI limits would be exceeded. Software set table bits associated with each connector port specify the desired bandwidth. For a hard reset, the link operates at its defaul...