Patent ID: 6215796
Filing Date: 2001-04-10
Classification: H04Q

Abstract:
In a system having a plurality of end-user devices coupled to a communications controller which is connected to an integrated services digital network (ISDN) line of a telecommunications network, the ISDN line having two bearer channels of predetermined bandwidth and a data channel, a method of subchannel bandwidth allocation comprising:establishing, as demanded for a particular end-user device, a call connection through the telecommunications network between the communications controller and another network terminator;inquiring, over the data channel, whether the network terminator is a compatible communications controller, wherein the compatible communications controller has a plurality of end-user devices coupled thereto, and wherein the plurality of end-user devices includes a plurality of telephones;responsive to receiving a positive compatibility indication, allocating by the two controllers to the particular end-user device a subchannel from the predetermined bandwidth of the two bearer channels, wherein the subchannel consists of bandwidth up to the predetermined bandwidth if the particular end-user device is a data processing unit or bandwidth sufficient for a controller-encoded voice signal if the particular end-user device is a telephone, and wherein the particular end user device is a data processing unit having been allocated the subchannel of bandwidth up to the predetermined bandwidth as a data subchannel;responsive to receiving the positive compatibility indication, each of the two controllers informing the other, over the data subchannel, of identifiers and types of coupled devices;responsive to not receiving the positive compatibility indication, allocating by the communications controller to the particular end-user device one of the two bearer channels;transmitting, over the subchannel or one bearer channel, outgoing signals from and incoming signals to the particular end-user device;dialing, at a first telephone of the telephones coupled to one of the two communications controllers, the identifier corresponding to a second telephone of the telephones coupled to the other controller; andthe one controller sending, on the data channel, a suballocation request for a voice subchannel to the other controller, wherein the suballocation request includes the identifier of the second telephone and specifies extraction of bandwidth from the data processing unit subchannel for the voice subchannel;the other controller investigating state of the second telephone, which state is either idle, busy or non-working, and reporting the state to the one controller;if the state is idle, the other controller instigating ringing at the second telephone and the one controller reflecting a ringing tone to the first telephone;if the second telephone is answered, the other controller ceasing to ring and transmitting on the data channel an accession message, coincident with which the other controller extracting sufficient bandwidth from the data processing unit subchannel to form the specified voice subchannel;after a specific period at close of the accession message, the other controller effecting the bandwidth changeover in its full channel transmission towards the one controller;the one controller transmitting an acknowledgement message on the data channel; andafter the specific period at close of the acknowledgement message, the one controller effecting the bandwidth changeover in its transmissions towards the other controller;whereby voice communication proceeds on the voice subchannel, using the controller-encoded voice signal, simultaneously with data transfer on the data processing unit subchannel.