Device and method to establish communication

摘要

The invention relates to a method and an apparatus to establish both telephone and digital communication through an interface between a subscriber unit and a Local Exchange on a telecommunication line intended for digital traffic, for instance an ISDN-line. For the telephone communication, the subscriber unit and the Local Exchange are communicating by transmitting packages according to a protocol comprising PSTN speech communication together with at least service functions through an interface between the subscriber unit and the Local Exchange.