A method includes disposing multiple medical probes to acquire physiological data concurrently from a living body. The data is sent from the multiple medical probes by transmitting over wireless channels respective sequences of data packets that are marked with respective packet numbers. A synchronization signal that is broadcast to the multiple probes is received in the probes. In response to receiving the synchronization signal, the packet numbers that are to be assigned in the probes to subsequent data packets in the respective sequences are reset.