Membrane switch for a telephone handset

Method and apparatus for controlling an exchange

Method and apparatus for determining digits dialed using a selec

Method and apparatus for improved call control scheduling in a d

Method and apparatus for maintaining real-time busy status infor

Method and apparatus for processing call number information for

Method and apparatus for universal telephone operator service

Method and device for controlling affiliation of remote...

Method and device for hunting for communication channel

Method and device for providing intermediate telephone...

Method and network for transmitting addressed signal samples fro

Method and system for compensating for signal deviations in tone

Method and system for distinguishing valid DTMF signals from spu

Method and system for distributing data to nodes in PBX network

Method and system for protecting equipment and switching...

Method for creating a telephone digital switching platform

Method for load distribution among the central processors of a m

Method for operating and apparatus for a back-plane...

Method for supporting session mobility

Method for switching active calls