Data transmission method employing a synchronous frame combining asynchronous cells with isochronous channels

A data transmission method employing a synchronous multiframe associating asynchronous cells and synchronous data octets to isochronous channels on a time-division multiplex link to transmit data during successive multi-frames, each multiframe comprising a plurality of numbered frames, said frames each being made up of a plurality of time slots and the time slots identically numbered in successive frames constituting an isochronous and octet-oriented data transmission channel, said method comprising the steps of:

• reserving a first time slot of each frame for management data that are independent of the data to be transmitted,
• reserving a second time slot of each frame for path service data, said path service data being divided according to the frame numbers, between a first group of the second time slots, having specific frame numbers, which are reserved for asynchronous data cell service octets, and a second group of the second time slots, each time slot of the second group of the second time slots being reserved from data indicating the number of time slots to be used for synchronous transmission during the frame corresponding thereto and optionally during the next frame if the second time slot thereof is a second time slot of the first group, and
• reserving a third time slot of each frame for a code defining a start-of-cell time slot number when a cell begins in the frame,
• the first, second and third time slots of the same frame being immediately successive to one another.