Abstract: A telecommunication system for transmitting and receiving data organized in packet of variable length among proprietary station by routing the data through a network equipped with switches handling data organized in standard packets or cells (ATM) each composed of a header followed by a payload of standard length. The system including: a first downstream interface (A), at transmitting end station, where cells of non standard size are initially formed; nodes (non standard nodes) equipped with at least one non standard interface adaptor means, able to handle non standard size cells; standard nodes (standard ATM world) equipped with standard interfaces only, able to handle standard size cells.