A method for transmitting data in a mobile radio communication cellular network, wherein setting up, maintaining and terminating a data communication channel between a caller and a called party located in the cellular network are implemented by the exchanges of signalling messages. A caller and/or a called party each is located in a local zone of the cellular network. The method includes: a first detecting phase if the caller and the called party of the communication are located in the same local zone of the cellular network, according to a detection strategy including a step of analysing all or a portion of the signalling messages; and then triggering a local loopback operation of all or a portion of the data exchanged between the caller and the called party, in the case where the detecting phase confirms the local nature of the communication between the caller and the called party.