Digital satellite exchange for calling subscribers

A digital satellite center for connecting analog subscribers and digital subscribers. It includes a digital control unit (NCU) and digital concentrators subscribers of at least one of the following types; local for analog subscribers (NACC) from distant for analog subscribers (CNEA), local for digital subscribers (CNLN) Distant type for digital subscribers (CNEN) and Distant mixed type (NCCM) for analog subscribers digital subscribers, each concentrator being connected to the control unit via a multiplex link (L1, L2, 9, 18, 28), the control unit providing a concentration of said multiplex links and being connected to a digital central office by a multiplex link (29).