Automatic id assigning device for network instruments

Abstract

An automatic ID assigning device for LAN instruments connected in a network assigns ID numbers from a master LAN instrument to respective slave LAN instruments connecting sequentially to the master LAN instrument. A first slave LAN instrument stores, as its own self ID, an ID number supplied in an ID assignment command signal supplied from the master LAN instruments through a data line connecting ports of respective slave LAN instruments. The slave LAN instrument returns an ID assignment acknowledging signal to the master LAN instrument and connects upper and lower ports of the slave LAN instrument together. The master LAN instrument updates a connecting number table of the ports of the slave IDs upon receipt of the assignment acknowledging signals and transmits a subsequent ID assigning command signal to another slave LAN instrument through the data line and through the connected ports of slave LAN instruments to which ID numbers have already been assigned. The upper and lower ports, i.e., the input and output administrative data lines, of the slave LAN instruments to which ID numbers have not yet been assigned are not connected to each other.