Patent ID: 6021138
Filing Date: 2000-02-01
Classification: H04W

Abstract:
A digital cordless telephone system comprising:a multiplicity of subscriber cordless handsets (HS's), a subscriber number of a private automatic branch exchange (PABX) being assigned to one or more of the HS's;a plurality of base stations (BS's), each of the BS's being coupled with one or more of the HS's by radio channels for controlling a radio link between each of the BS's and each of the HS's, a 32 kbps adaptive differential pulse code modulation (ADPCM) speech signal being transferred between one of the HS's and one of the BS's,wherein each of the BS's includes:first multiplexing/demultiplexing means for multiplexing four 32 kbps up-stream ADPCM signals to two 64 kbps up-stream speech channel signals and demultiplexing two 64 kbps down-stream speech channel signals to four 32 kbps down-stream ADPCM signals;first controlling means for converting an up-stream CAI (Common Air Interface) control channel signal to a 16 kbps up-stream ISDN D channel protocol signal and converting a 16 kbps down-stream ISDN D channel protocol signal to a down-stream CAI control channel signal; andfirst interfacing means for assembling the two 64 kbps up-stream speech channel signals and the 16 kbps up-stream ISDN D channel signal into a 144 kbps up-stream ISDN BRI signal and disassembling a 144 kbps down-stream ISDN BRI signal into two 64 kbps down-stream speech channel signals and the 16 kbps down-stream ISDN D channel signal; andsystem connecting means coupled with the BS's and the PABX for allowing only authenticated HS's to initiate outgoing calls and for keeping track of each of the HS's to set up calls for the HS's whenever the HS's are within the service area of one of the BS's, wherein said system connecting means is coupled with each of the BS's through a subscriber cable having an ISDN basic rate access interface capability, two B type channels of a transfer speed 64 kbps and a D type channel of a transfer speed 16 kbps being included.