Method and communication compatibility formatting device on network terminals, for example to enable a dialog with an application on a smart card

In order to set up a communication channel on a link connecting a client application on a client machine and a service application present on a device dependent on a terminal, the client machine includes a representative of the service application. A formatting module is located at the client machine, downstream of the representative, for formatting the client application messages in a form readable by the service application. A gateway is located at the terminal, for receiving the messages readable by the card and transmitting them to the service application. Typically, the communicating device is a smart card, and the service application is a card application. The link is typically a network, for example of the Internet type.