Abstract: In order to store data in a mobile telecommunications system, a data storage unit (HLR) has data functions (72, 74) providing data redundancy therebetween, control functions (79, 80) and signalling point (30, 31, 32) to enable the data storage unit to pass data to and from a mobile telecommunications network under the control of the control function. The control functions are physically separate from the data functions. The data functions (72, 74) may operate on the basis that one has a primary data function, a second has a primary standby function to achieve synchronised updating. The use of separate and hence distributed functions enables greater flexibility in the retrieval of data from the data storage unit (HLR).

Abstract: A mobile telephone network has a function (30) which interacts with the platform (40) or platforms processing a call, event or session to: a) determine the services and/or call handling operations to be applied to the call, event or session; and b) determine if the platform(s) (40) are capable of carrying out the services and/or call handling operations required by the call, event or session. The function may then arrange for the platform (40) to be provided with appropriate data or for the call, event or session to be transferred to another platform. Moreover, a call may have part of its data converted into a standard protocol, and the data in that standard protocol then be used to guarantee a trigger for processing the call at a transfer device.