Importance

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Abstract

A communications controller for interfacing multiple analog telephone terminals to an integrated services digital network (ISDN) line connected to a telecommunications network, the ISDN line having two bearer (B) channels and a data (D) channel. The controller comprises an ISDN interface providing a physical bi-directional interface to the two B-channels and the D-channel of the ISDN line. A base logic processor, and D-channel protocols process supports a Q.931 protocol with a central office of the telecommunications network and an X.25-based protocol with a remote device, via the ISDN interface and D-channel over which command and response packets to and from the base logic processor with the central office or the remote device are transmitted. Multiple analog interfaces are adapted to support respective telephone terminals for passing bi-directional analog voice signals. Selectable coders/decoders (CODECs), connected to respective analog interfaces, encode the analog voice signals to digital pulse code modulation (PCM) or adaptive differential PCM (ADPCM) and decode PCM or ADPCM to analog, as selected by the base logic processor. A bandwidth controller connects, via the ISDN interface, the encoded voice signals to or from the selectable CODECs with communication subchannels allocated among bandwidth of the B-channels, as directed by the base logic processor, forwarding precisely timed bandwidth availability. The communications controller supports up to five telephone connections concurrently through the telecommunications network.

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First Claim