US 5,398,248 AGranted

Resolving conflicts between communication systems

AssigneeU.S. Philips Corporation

InventorRobert Shepherd

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Abstract

First and second independent communication systems are linked across an intersystem interface by a virtual circuit constituted by a land line linking the central stations of both systems. Occasionally both central stations may attempt to simultaneously use the virtual circuit, which cannot be done for digitized speech because in that case the virtual circuit operates as a simplex link. A method of resolving this conflict is disclosed, whereby one of the central stations is issued a token by the other entitling the holder of the token to use the virtual circuit. After the transaction is completed, the token is then returned. Two algorithms are disclosed, one based on the last user of a token giving it to the other user, and the other of which takes into account the number of registered secondary stations in each system.

Claims7

Dependent claims

A method of resolving conflicts between two communication systems of equal status and which are linked by a virtual circuit providing at least a simplex communication path;

each of said systems comprising a central station and at least one secondary station having transceiving means, the central station including a system controller and base station transceiving means, said method comprising the steps of:
(i) transmission by the central station of a first of said systems of a token request to a second of said systems by way of the virtual circuit, for authorization to set up a calling path by way of the virtual circuit between the first system and the second system;
(ii) checking by the system controller of the second system to determine if there is a request from a secondary station in the second system to make a call by way of the virtual circuit;
(iii) granting of said token request by the system controller of the second system if the determination made in step (ii) is in the negative;
and
(iv) in response to the granting of said token request, setting up by the central station of the first system of a point to multi-point calling path from the first system to the second system by way of the virtual circuit.

3 more elements

A combination comprising:

two communication systems of equal status, each comprising a central station and at least one secondary station having transceiving means, the central station including a system controller and base station transceiving means;
a virtual circuit interconnecting the central stations of the two systems and providing at least a simplex communication link there-between;
the central stations of the two systems being adapted to transmit token requests to each other by way of said virtual circuit and said base station transceiving means, a token request being a request for the granting of a token to authorize use the virtual circuit;
the system controller of each central station being adapted, in response to reception of a token request, to check whether a secondary station in its own local system has issued a transmission request requiring use the virtual circuit, and if not, to grant the received token request;
and
the system controller of each central station being further adapted, upon the granting of its token request, to cause said central station to set up a point-to-multi-point calling path to the opposite one of said systems by way of said virtual circuit.

3 more elements

Dependencies are inferred from the claim text.