That pressure, with valves 26B and 26D open, in turn draws gas from chamber 26E and through chamber 26C, thereby generating an electrical signal at rectifier 26F. As the reservoir 21 is depleted of medicant, a device such as a syringe may be used to pierce the skin and penetrate the septum 18, followed by injection of a liquid phase medicant or other infusate into reservoir 21, thereby replenishin