Abstract: A method and a communication network including a public telephone network and a narrow band radio network for packet-switching of data between stationary and mobile terminals. Voice messages may be bi-directionally transferred between the public telephone network and the terminals by a gateway arranged to connect the public telephone network and the packet-switched narrow band radio data network. The voice messages are converted in the gateway or terminals into digital form and compressed, and then transferred to the packet-switched narrow band radio data network. The terminals and the gateway are provided with a device in which the compressed voice messages, transferred through the packet-switched network, are expanded and, after conversion to analog form, reproduced.