Abstract: A method (300) for carrying out a security procedure with a mobile station, where a hybrid cellular telecommunication system communicates with a mobile station (301) and the hybrid cellular telecommunication system communicates with a cellular network (308). The method is characterized in that the cellular network carries out the security procedure with the mobile station, the data related to the security procedure is transferred between the cellular network and the mobile station via the hybrid cellular telecommunication system, and the decision of triggering the security procedure of the cellular network is made outside the cellular network (309). The invention also relates to a network element (510) in the hybrid cellular telecommunication system that triggers the security procedure and to a network element (500) in the cellular network that carries out the security procedure after receiving a triggering signal.

Abstract: A network for communicating with a plurality of radiotelephones via respective communication channels over timeslots on a carrier, wherein the channels can operate at a first or second data rate such that a timeslot on the carrier can transmit a single communication channel operating at the first data rate or two communication channels operating at the second data rate, the network comprising a controller responsive to a predetermined condition for initiating a change in the data rate of two channels transmitted on separate timeslots from the first data rate to the second data rate.

Abstract: A method for establishing a packet data connection in a telecommunications system which includes an office network, an operator network, and a local area network between them. Data transmission from the office network through the local area network is adapted to a data transmission protocol according to a mobile system. The office network also includes a serving support node, a packet control unit, and a gateway support node, which are arranged to support the packet data protocol of the mobile system. The serving support node, packet control unit, and gateway support node are arranged to have a functional connection with each other and with a radio access gateway. A packet data connection request is made from a mobile station to the office network, and a packet data connection is established from the serving support node and gateway support node to a destination address defined by the link request.