Hinge mechanism comprising first and second frames rotatably mounted relative to one another, the first frame comprising a collet, a control member rotatably mounted in the collet of the first frame and controlling a relative rotation between the two frames, and a brake unit comprising an operating member connected to the control member with angular play. The first plurality is greater than the second plurality, the reduction in number from the first plurality to the second plurality being based on the determined time at which the second communications device is in a ready state. Spring is covered with hose cover material on the outside and hose cover material on the inside to form a sealed hose and are bowed inward or outward radially between the individual spring coils depending on the intended use of hose to give the cover materials room to move out of the way when the hose retracts and the coils of spring are forced close together. A pump is fluidly connected to the canister and is configured to draw wound exudate from the dressing into the canister when the first valve is open and the second valve is closed.