Abstract: A wedge locking element (10) for a locking device of a quick coupler A for coupling the pin P2 of an attachment to earth working machinery. The wedge locking element (10) has a sloping wedge surface (13). Projecting from the wedge surface (13) is an engagement surface (12) with which the attachment pin P2 can engage but not apply any substantial driving force to the wedge locking element (10) in the event of failure of a force maintaining the wedge locking element (10) in a position where the pin P2 is retained with the coupler A. The pin engagement surface (12) lies in a plane that is substantially in line with the direction in which the locking element (10) is, in use, moved by the driving force.

Abstract: A first device detects whether a second device implements full duplex communication. When the first device begins receiving a network packet from the second device, the first device transmits a jam signal to the second device. When transmission of the network packet from the second device to the first device has been completed, the first device determines whether a check value within the network packet is valid. When the check value is valid, the first device recognizes that the second device implements full duplex communication. When the check value is not valid, the first device recognizes that the second device does not implement full duplex communication.