frame whereby the order of time slots in a stream of output data is always from an earlier time slot to a later time slot application_number US 36189299 A description turning to fig1 a pair of sequential frame intervals labelled frame a and frame b are illustrated the line labelled input data illustrates four incoming time slots carrying time slot numbers 2 3 4 and 1 it is desired to apply data from incoming time slots to outgoing time slots such that the data which is in order in the incoming time slots is in order in the outgoing time slots this will be referred to below as the connection of incoming to outgoing time slots the assignment of time slots in the two data streams of input data and output data is arbitrary however as shown in fig1 the incoming and outgoing frames are aligned there is no requirement that the pattern of outgoing time slots should depend on the pattern of incoming time slots if the data in the incoming time slots for example were in order by channel abcd connections would be made such that the outgoing data would be again be in order by channel abcd with the minimum delay the system using well known methods identifies a framing pattern that is contained within the incoming data.