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Method and apparatus for selecting a cellular system for communication with a cellular telephone in a roaming area

  • US 5,787,347 A
  • Filed: 12/11/1995
  • Issued: 07/28/1998
  • Est. Priority Date: 12/11/1995
  • Status: Expired due to Term
First Claim
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1. A method for selecting a cellular system for communication with a cellular telephone in a roaming area, said cellular telephone having a home cellular system in a home service area, said method comprising the steps of:

  • said cellular telephone transmitting a system access message to a default cellular system;

    when the default cellular system that receives the system access message is a visited cellular system in the roaming area and the cellular telephone is not registered with the visited cellular system, said visited cellular system registering the presence of the cellular telephone in the roaming area with the home cellular system;

    said home cellular system sending a response including a selection indication to the cellular telephone through the visited cellular system, said selection indication containing selection information for controlling selection of a cellular system for communication with said cellular telephone in the roaming area, wherein said selection information includes one of a negative SID indication, and a retune indication; and

    said cellular telephone selecting a cellular system for communication in the roaming area in accordance with said one of the negative SID indication and the retune indication.

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