Abstract: An interface device for an ATM network permits a plurality of ATM devices to be connected to a single ATM switch port. The interface device, in its preferred embodiment, is a modular device which may be interconnected to form a system having various segment arrangements to suit the system operational requirements. Each interface device may include a switch side connector, extension side connector, and a device side connector all on a single card with the interface device being configured in VSLI architecture, and multiple interface devices interconnected to construct the system segments. In an alternate application, the interface device may be used to replace the computer backplane and provide direct connection between a computer's system components and an ATM network. In still another configuration, the interface device may itself be utilized to interconnect a plurality of computers to form a local area network.