US Patent 7480290 Network switching system with asynchronous and isochronous interface

A switching system may include a gateway node connected with ISDN (Integrated Services Digital Network) and PSTN (Public Switched Telephone Network), and one or more extension nodes, and a serial bus such as IEEE 1394 bus. The gateway node may transform the data rate of an outside line into a data rate of the extension node, and vice versa, and secure a seamless communication channel. The gateway node may secures an isochronous channel, according to a request from the extension nodes or the outside line, and may executes switching such as transfer or reservation. A resource manager may hold a table for managing the gateway node and extension node.