A device is disclosed for compressing data contained in input frames to be compressed constituted of stream frames defining portions of TRAU and signaling frames that have to be transmitted within a communication network and each of which is constituted of at least a header containing control data representative at least of the type of stream frame and where applicable payload data, certain types containing critical and/or non-critical data. The device analyzes each TRAU or signaling frame header contained in successively received input frames in order to determine its type and generates periodically compressed frames to be transmitted that are divided into first and second sections of variable size. The first section contains critical data compressed synchronously and the second section contains non-critical data compressed asynchronously.