the synchronization arrangement includes a waveform and synchronization information generator to supply synchronization information for transmission with a data stream over digital switching networks . the synchronization information includes two different patterns , phased displaced with respect to each other . interfaces connect peripheral devices to the networks and are adapted to detect a validate the synchronization information . the checks made are in respect of detecting both patterns , the amount of phase displacement , and the correct sequence . if the synchronization information is invalid , the detecting interface selects a data stream from another network exclusively for use by the corresponding peripheral device .