In a telecommunications network including a core network component and first and second telecommunications devices, with the second telecommunications device being associated with a SIM which is not directly routable in the telecommunications network in regard to communications with the first telecommunication device, a method of transmitting a communication between the first device and the second device including: the core network component receiving a communication from or for the second device via a data bearer; and configuring the core network component, to encapsulate the received communication and forward the encapsulated communication to a management server external to the telecommunications network so as to obtain appropriate routing data and/or routing authorization for the communication.