Motorola Solutions, Inc.

Motorola Corporation

Sikendar Fidai

Donald G Newberg

Trent J Miller

Michael F Korus

Peter M Drozt

Scott James Pappas

Rod N Averbuch

Brian R Poe

Steven E Vanswol

Todd A Leigh

Gerald R Drobka

Anatoly S Belkin

Kamala D Urs

Jay R Krebs

Robert L Epsom

Laura A Christensen

A hosted inter-radio frequency subsystem interface (HIF) maintains a list of affiliated radio frequency subsystems (RFSSs), the list identifies at least one serving RFSS. An affiliation request is transmitted from the HIF to the home RFSS, which is a home RFSS of the group. The HIF receives from the serving RFSS a request to initiate an inter-RFSS group call to the group using HIF addressing. The HIF transmits a request to the home RFSS to initiate the inter-RFSS group call using serving RFSS addressing. A data packet from the home RFSS or the serving RFSS is received at the HIF. Upon receipt, the HIF transmits a copy of the data packet to the serving RFSS if the data packet was received from the home RFSS; otherwise, the HIF transmits a copy of the data packet to the home RFSS if the data packet was received from the serving RFSS.

Method and device for establishing an inter-radio frequency subsystem interface (ISSI) group call

A method and device enable establishing an inter-radio frequency subsystem interface (ISSI) unit-to-unit call between a calling unit of a calling home radio frequency subsystem (RFSS), and a called unit of a called home RFSS, through a hosted ISSI function (HIF). The method includes processing, at the HIF, a first invite message received from the calling home RFSS, wherein the first invite message includes a first request uniform resource identifier (URI) that designates an alias system unit identification (SU-ID). In response to the first invite message, transmitting, from the HIF to the called home RFSS, a second invite message, including a second request URI that designates a real SU-ID, wherein the HIF acts as the calling home RFSS. The unit-to-unit call is thus established between the calling unit and the called unit through the calling home RFSS, the HIF, and the called home RFSS.

Method and device for establishing an inter-radio frequency subsystem interface (ISSI) unit-to-unit call

A calling communication unit (210) transmits a dispatch communication request to a communication infrastructure (202). The dispatch communication request includes at least a dispatch identification of a called communication unit (e.g.,216). In response to the dispatch communication request, the communication infrastructure generates an alert message that includes a dispatch identification of the calling communication unit and determines a telephone number associated with the called communication unit. The communication infrastructure then transmits the generated alert message to the called communication unit based on the telephone number associated with the called communication unit.

Method and apparatus for alerting a communication unit in a

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South Barrington, IL, United States of America

Sikendar Fidai