Abstract: The number of the earth stations in a TDM channel is limited, along with the increase of the earth station, one TDM channel can’t send control injunction to all the earth station, so this thesis proposes a conception which is more TDM control channels, extending the TDM channel from one to more, achieving the grouping of the earth station and the switching between the channels. In the basis of the parameter, the earth station setting the value in the channel chooses field. On duty of the correlational TDM channel, the system takes the reserved of the channel for every TDM.

Key words: VSAT, TDM, net center