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Adaptor between ISDN basic rate access and switched-56 accesses

  • US 5,479,405 A
  • Filed: 04/28/1994
  • Issued: 12/26/1995
  • Est. Priority Date: 04/28/1994
  • Status: Expired due to Fees
First Claim
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1. An adaptor for permitting an ISDN telephone device which receives and transmits digital data in accordance with CCITT Recommendations for ISDN Basic Rate Access to exchange digital data with a Switched-56 Access to a telephone network which transmits and receives the digital data in accordance with a Switched-56 protocol, said adaptor comprising:

  • an ISDN Basic Rate Access interface circuit adapted for providing an ISDN Basic Rate Access with which an ISDN telephone device exchanges digital data in accordance with the CCITT Recommendations for ISDN Basic Rate Access;

    an adaptor bus for exchanging the digital data with said ISDN Basic Rate Access interface circuit;

    a Switched-56 Access interface circuit adapted for interconnecting with a Switched-56 Access to the telephone network with which said adaptor exchanges digital data in accordance with the Switched-56 protocol, said Switched-56 Access interface circuit also exchanging such digital data with said adaptor bus included in said adaptor;

    a random access memory coupled to said adaptor bus for storing the digital data respectively received by said ISDN Basic Rate Access and Switched-56 Access interface circuits, and for respectively supplying the stored digital data for transmission by said ISDN Basic Rate Access and Switched-56 Access interface circuits;

    a programmable digital signal processing circuit coupled to said adaptor bus for controlling operation of said ISDN Basic Rate Access and Switched-56 Access interface circuits and of said random access memory; and

    a clock recovery circuit for synchronizing the digital data transfers occurring between said ISDN Basic Rate Access interface circuit and the ISDN telephone device with the digital data transfers occurring between said Switched-56 Access interface circuit and the Switched-56 Access.

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