A communication between a client device (2) and a peripheral unit (14) uses tunnelling over another communication mode. The other communication mode is implemented between the client device and a host device (1), in addition to a communication mode implemented between the host device and the peripheral unit. The host device and the client device are each provided with additional communication modules (3-6), at application level and transport level. Security issues against intrusions into the communication may be implemented by the modules added to the host or client unit.