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Browse Prior Art Database

ISDN S/T/U AUTOMATIC DETERMINATION AND ACTIVATION INTERFACE

IP.com Disclosure Number: IPCOM000006660D
Original Publication Date: 1992-Dec-01
Included in the Prior Art Database: 2002-Jan-21
Document File: 2 page(s) / 108K

Publishing Venue

Motorola

Related People

Eric Crane: AUTHOR

Abstract

The telephone operating companies in the United European F7T's offer ISDN service at the S/T interface/ States offer ISDN service at the U interface, and the as shown in the diagram below.

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INC. Technical Developments Volume 17 December 1992

ISDN S/T/U AUTOMATIC DETERMINATION AND ACTIVATION INTERFACE

by Eric Crane

BACKGROUND

The telephone operating companies in the United European F7T's offer ISDN service at the S/T interface/ States offer ISDN service at the U interface, and the as shown in the diagram below.

U.S. Demark

I

European Demark CCITT ISDN Reference Model (simplified)

  The S/T interface utilizes a four wire transmission scheme, while the U interface utilizes a two wire trans- mission scheme. As a result, the S/T interface and U interrface are incompatible at layer la.

  ISDN terminal equipment intended to operate in the U.S. and Europe must implement both interfaces and rely upon the user of the equipment to determine which interface is offered at a given location. This prob- lem is compounded in the U.S. when value added ISDN service resellers offer an S/T interface instead of the U interface. For example, a hotel operator buys ISDN serv- ice from the local telephone company and resells the service in hotel rooms to guests using the S/T interface. Domestically, a reseller is free to offer ISDN service at the U or the S/T interface which may propagate a mix of U and S/T interface offerings within the United States.

PROBLEM

  This mix of incompatible service offerings at the physical layer causes confusion and burdens users with 'The
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becoming knowledgeable about and troubleshooting con- nections to ISDN services. Additionally, ISDN terminal equipment manufacturers have the problem of which interface to implement for a given ISDN terminal product.

SOLUTION

  The ISDN S/T/U Automatic Determination and Activation Interface solve these problems by a...