A method and apparatus for a connection interface between a reservoir or syringe, infusion set tubing, and an infusion pump is provided. A base is provided which is adapted to receive a reservoir. The base has a base engagement member, such as a detent, projecting therefrom. A cap is provided which is adapted to receive the base. The cap includes a first cap engagement member, such as a detent opening, which is adapted to removably engage the base detent. The cap further includes a second cap detent opening which is adapted to removably engage the base detent. A piercing member, such as a needle, is disposed in the interior of the cap in such a manner that the needle is separated from the reservoir septum when the base detent is in the first cap detent opening, and the needle pierces the reservoir septum when the base detent is in the second cap detent opening. When the reservoir, the base and the cap are connected to form an integrated unit, this unit is then capable of being inserted and secured in the infusion pump housing.