Abstract: A network interface card for attaching computers, work stations or the like to a Local Area Network (LAN) includes a device which indicates an address compare if selected bits in a first part of an address, in the address field of a received frame, matches bits stored in the network interface card and at least one bit of a code word stored at a particular address of an index RAM is set to a predetermined state. The particular address in the index RAM is identified by a second part of the address in the received frame. The range of address which can be recognized is further extended by a contents addressable memory (CAM) coupled to the device. The CAM makes a parallel compare between an input address and its contents and outputs a match signal if a match is found. A programmable control register is used to activate or deactivate the CAM or the device.