Method for multiple access in a digital communication system

A digital data communications system, comprising a master station;

• a plurality of slave stations;
• a multidrop 2B+D ISDN digital link comprising two base rate channels B1, B2 and one data channel D from said master station to said slave stations and two base rate channels B1, B2 and one data channel D from said slave stations to said master station, said digital link being connected to said master station;
• said plurality of slave stations associated with the channels of said digital link distributed at points along said digital Link and communicating with said master station via said digital link over said slave to master channels in a time compression multiplex scheme employing data bursts, said master station including means for transmitting in a multiplex frame a master burst over said master to slave channels, and means for receiving in the multiplex frame slave bursts from the respective slave stations;
• and said slave stations each including means for transmitting slave bursts over respective channels associated therewith in said multiplex frame;
• and said transmitting means at said slave stations transmitting said slave bursts in time windows spaced within the multiplex frame to allow for propagation delays along said link and prevent bit interference in said receiving means at said master station.