<p>A method of establishing a communications session for communication of data between a mobile telephony device and a data communication device in a data communications network. The mobile telephony device has both voice and data communication capabilities. Call party details of a telephone call are received. The telephone call involves at least the mobile telephony device and a further telephony device that is associated with the data communication device. The call party details include a first identity associated with the mobile telephony device and a second identity associated with the data communication device. At least one of the first and second identities comprises a telephone dialling number. A separate communications session is established on the basis of the first and second identities received in the call party details. The communications session is separate from the telephone call and is for the communication of data between the mobile telephony device and the data communication device. Establishing the communications session comprises communicating with the mobile telephony device and the data communication device.</p>
