The frame structure according to G.704 is based on G.703. G.704 is used to frame the data rates of 1,544 kbit/s, 2,048 kbit/s, 6,312 kbit/s, 8,488 kbit/s and 44,736 kbit/s specified in G.703. Individual channels of G.703 can be distinguished by the frame structure with the 64-kbit/s time slots. Time slot
0 is reserved for the frame password. In the broadband service switch, only the time slots occupied by the user are transmitted.