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Radio communication device capable of communication in a plurality of communication systems

  • US 5,640,686 A
  • Filed: 05/12/1995
  • Issued: 06/17/1997
  • Est. Priority Date: 05/13/1994
  • Status: Expired due to Term
First Claim
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1. A radio communication device comprising:

  • a main communication unit capable of effecting communications in a first digital cellular communication system; and

    an additional unit attachable to said main communication unit for effecting communications in a second digital cellular communication system which differs from said first digital cellular communication system;

    said main communication unit including a first component having a function which is the same as a function of said additional unit, and other components compatible with both said first digital cellular communication system and said second digital cellular communication system;

    the arrangement being such that switching is made from said first component to said additional unit when said additional unit is attached to said main communication unit, and thereby said radio communication device is capable of switching communication to said second digital cellular communication system;

    said main communication unit including;

    a transmission system including a power amplifier as said first component compatible with said first digital cellular communication system;

    a variable-bandwidth filter having a bandwidth variable depending on said first digital cellular communication system and said second digital cellular communication system; and

    a central processing unit having a protocol which can be changed depending on said first digital cellular communication system and said second digital cellular communication system; and

    said additional unit including;

    a power amplifier compatible with said second digital cellular communication system;

    the arrangement being such that switching can be made between said power amplifier in said transmission system and said power amplifier of said additional unit.

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