Patent ID: 6650625
Filing Date: 2003-11-18
Classification: H04L

Abstract:
A ring network system in which a plurality of network devices each having a first communication control unit for controlling data communication are connected in a ring-like manner by a transmission line to mutually effect transmission and reception of data among the network devices, comprising:an addition unit disposed between two adjacent ones of said plurality of network devices, said addition unit and said plurality of network devices being connected in the ring-like manner by said transmission line, wherein said addition unit has a plurality of device inserting slots in which a plurality of additional devices are installed and which are provided in correspondence with said plurality of additional devices, a second communication control unit for controlling data communication among said plurality of additional devices installed in said plurality of device inserting slots and for controlling data communication between said additional device and said network devices, and a device determining unit which, on the basis of a signal sent from said additional device installed in said device inserting slot, determines whether said additional device is said network device having said first communication control unit or a non-network device not having said first communication control unit.