Abstract: A system for processing parcel shipping comprises a set of "file memories" (2) containing firstly the identities of carriers, of senders, of the services offered by each carrier, of the documents that should accompany each shipment, and of the access of each sender to the various carriers and their services, and secondly receiving characteristics relating to each shipment, a programmed control unit (3) coupled to the files to generate and control the storing of characteristics specific to each shipment, document printers (10-13) for generating the documents for each shipment, the printer including a postage meter (13). The system further includes scales (14), and being characterized in that it includes an electronic card (20) for insertion into the processor unit to supervise its connection with the postage meter (13) and the scales (14), and to monitor and lock the software of the system by intervening in data exchanges between the programmed control unit (3) and the set of memories (2).