PURPOSE: To provide a device for decoding the address of a printed wiring circuit card from a mother board by supplying address data and a control signal to a bus connected to the mother board.

CONSTITUTION: In this automatic slot identifying and address decoding device having a mother board MB for transmitting address information, data and control signal to printed wiring circuit cards 1-1d, specified addresses to the respective printed wiring circuit cards are set by electric cable connectors (plug connectors 4-4d and receptacle connectors 7-7d). The respective printed wiring circuit cards are provided with programmable logic devices Ul-Ud for dynamically recognizing the address information received from the mother board MB and electronic circuits for transmitting the data and control signal to the electric cable connectors.