An ISDN interface for the PC compatible

Low bit rate ISDN (2B+D) connections are becoming available especially within a PABX. An interface card is described that allows IBM/sup TM/ PC compatible computers to connect to the ISDN. The design is innovative in that the interface operates as a COMx port obeying the HAYES/sup TM/ command set, as a memory mapped interface for customized applications and finally as a voice interface for telephony. The HAYES/sup TM/ mode allows the user to take advantage of the host of communications based software on the market. The paper also discusses the integrated circuits chosen to support the complex hardware interfaces required by the ISDN standards.<
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