A station in a communications network determines the mode (full-duplex or half-duplex) in which it communicates with a concentrator port by establishing a Registration routine between the station and the concentrator port. The station and concentrator port exchange frames which disclose the capabilities...http://www.google.de/patents/US5561666?utm_source=gb-gplus-sharePatent US5561666 - Apparatus and method for determining operational mode for a station entering a network
