A videoconferencing center (31, 33) for data communications and teleprocessing is provided which comprises first routing switches having a plurality of sending ports (51, 53, 55, 57) and a plurality of receiving ports (50, 52, 54, 56), each sending port adapted to be operatively connected to a receiving data terminal equipment unit (10, 28, 29) or to a receiving port of second routing switch (32, 34), each receiving port adapted to be operatively connected to a sending data terminal equipment unit (10, 28, 29) or to a sending port of another group switching center (32, 34). Each receiving port is assigned a receiving stack (102) that is addressable in a single logical address space and each sending port is assigned a sending stack (103) for containing addresses of said single logical address space. The single logical address reduces the risk of losing data received, which risk results from the necessary limits on physical addresses of stacks. This group switching center is particularly useful for high-speed links of the type that may be required for a videoconferencing system.