Patent ID: 6865188

Claim:
A local communication system comprising: a plurality of stations interconnected by data carrying segments so as to form a ring network, each station comprising a network interface for transmitting data onto a respective segment of the ring network for receipt by the network interface of a subsequent station, whereby the network interfaces of all stations are operable at data rates synchronized with a single master clock, and wherein the network interfaces of at least two stations in the system are operable such that the data rate in a first segment of the ring is higher than that in a second segment of the ring, while remaining synchronized with said master clock, wherein synchronization is maintained by the provision of a regular frame structure which has the same frame period in both segments of the network, but a larger quantity of data in each frame of the first segment, and wherein each frame conveys control bits forming part of a control message frame transmitted over plural frames over all segments of the ring, successive control message frames forming a control channel shared by all stations of the ring network and having a constant data rate for control information in all segments.