ds-0,ds-1,ds-2,ds-3,ds-4 all are component. ds-0 is a single digital channel of 64kbps. ds-1 is a 1.544Mbps component. One ds-1 is made with 24 ds-0. By 4 ds-1 / 96 ds-0 we get 1 ds-2. ds-2 has 6.312 Mbps capacity. ds-3 is a 44.376Mbps component made by 672 ds-0 / 28 ds-1 / 7 ds-2 channels.  ds-4 has 274.176 Mbps capacity. ds-4 is made by 4032 ds-0 / 168 ds-1 / 42 ds-2 / 6 ds-3 channels.