Abstract: A multiple application switching platform includes a switch having a distributed open architecture and incorporating redundancy for enhanced fault tolerance. The switch includes at least one shelf having a midplane (1) containing message buses and TDM data buses (A and B). Shelves may be interconnected to form a group wherein various circuit cards are connected to each shelf midplane. The circuit cards (4, 5 and 6) perform call processing wherein each card within a group accessing a data bus is pre-assigned a unique set of time slots for each data bus within which that card may transmit onto that data bus. Each circuit card further includes an identification number that enables each card an opportunity to transmit onto a message bus (A and B). The circuit cards (4, 5 and 6) include line or trunk switch cards that function as an independent switch to interface line or trunks to a shelf midplane.