At+t Corp.

American Telephone and Telegraph, Co.

George P Cotsonas

Dale E Lynn

Edwin A Muth

Kenneth Kasiske

William J Casey, Iii

Dale Everett Lynn

A cordless telephone public base unit employed in a public telephone system in close proximity with other public base units effectively avoids contention with these other base units for access to a cordless telephone handset unit generating a service request. Contention between the public base unit and the other public base units is resolved by assigning a specific one of a plurality of times during which the base unit may respond to the service request from the handset unit. The time in which the base unit responds to the service request may advantageously be determined by a randomly generated number, the received signal strength of the service request or a combination of these two parameters. Once access to the handset unit is acquired by a base unit and communications between these two units is established on a communications channel, all other handset units and base units are prevented from interfering with the communications between these two units.

Method and apparatus for resolving contention between multiple base

In a public cordless telephone system, a cordless telephone handset unit requests and establishes a communications link with a public base unit served by a desired local service provider whenever possible. By generating a service request containing a specific carrier request code, the handset unit selectively identifies an available public base unit served by the desired local service provider and then establishes a communications link with this base unit. In response to receiving the service request from the handset unit, all public base units operated by the chosen service provider respond by providing a first acknowledgment signal. All other public base units respond by providing a second acknowledgment signal. When both such signals are received, the handset unit responds only to the first acknowledgment signal and establishes a communications link with the first base unit providing this signal. When only the second acknowledgment signal is received, the handset unit responds by establishing a communications link with the first base unit providing this second acknowledgment signal. When communications is established with a base unit providing the second acknowledgment signal, an alerting signal is generated at the handset unit thereby informing the user that even though he or she is able to make a telephone call, the desired local service provider was not reached. Collision avoidance between public base units while supporting this operation may be provided by assigning a specific one of a plurality of times during which each public base unit may respond to the service request from the handset unit.

Method and apparatus for selecting a preferred service provider during a

Growing community of inventors

Freehold, NJ, United States of America

George P Cotsonas