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Fixed cellular technical with a distinctive dial tone to indicate an emergency call is being placed

  • US 5,680,439 A
  • Filed: 04/28/1995
  • Issued: 10/21/1997
  • Est. Priority Date: 04/29/1994
  • Status: Expired due to Fees
First Claim
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1. A fixed cellular terminal (4) for use in a cellular mobile network (CS) that communicates, via radio, with at least one base station (3) in order to provide voice and/or data communications services to at least one subscriber terminal (5) that could connect directly to a public switched network, and which in addition to the basic communications service also supports an emergency call service when such calls are made from the subscriber terminal, said fixed cellular terminal including means (41) to generate one of a plurality of user signalling tones directed to the subscriber terminal for indicating line avability for dialing a telephone number and characterised in that said means (41) also has means for generating an emergency call dial tone, different from the one of a plurality of user signalling tones initially present;

  • a control circuit (42), connected to said means for generating one of a plurality of user signalling tones initially present, so as to control said means to generate one of a plurality of user signalling tones or the emergency dial tone, so that the emergency dial tone is generated when the control circuit determines that only emergency calls can be placed through the fixed cellular terminal when said control circuit determines that authorized subscriber identification has not been entered; and

    means for interfacing the generated emergency call dial tone to the subscriber terminal.

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