In a communication node (10) which comprises switching device (24) operating under control of a clock signal of period T for exchanging information slots carried in external frames of period T' comprising n slots, with each slot comprising a x-bit data byte, between external Time Division Multiplex TDM links (12,14) attached to the communication node, a synchronization device prevents the slippage phenomena due to the asynchronies between T and T' from causing a loss of data slots by generating at the input of the switching means internal frames from the received external frames. These internal frames are synchronous with the clock signal of period T and have a format which allows the slippage to be compensated.