Patent ID: 7852857

Claim:
A network coupler comprising: an external interface, for linking to a network on which Ethernet messages can be transmitted; and an internal interface, for linking a plurality of subscribers in series to a ring-type transmission path, with an Ethernet message received via the external interface forwarded to the internal interface and output onto the ring-type transmission path, the Ethernet message comprising a header, a trailer, and a data area between the header and trailer, the data area including a plurality of data blocks each assigned to one of the plurality of subscribers, wherein, upon the Ethernet message passing through on the ring-type transmission path, each subscriber connected to the internal interface interchanges useful data intended for the subscriber with the Ethernet message circulating on the transmission path as it passes through the corresponding subscriber, such that the subscriber takes data from the data block assigned to the subscriber in the data area of the Ethernet message and inserts data into the data block assigned to the subscriber in the data area of the Ethernet message.