An apparatus and method for supplying anesthetic agent to an anesthesia system is disclosed herein. The system is connecting detachably with at least two such apparatuses. The apparatus includes a storage volume for a liquid anesthetic agent and a space for evaporating the liquid agent. The apparatus also includes a gas inlet port for receiving a fresh gas for mixing with evaporated agent and a gas outlet port for conducting the gas mixture including evaporated agent to the system. The apparatus also includes a logic circuit for controlling anesthetic agent supply and an apparatus signal connector (50) to exchange information. The apparatus signal connector includes at least one first apparatus contact (60) for receiving from the system a signal indicating whether anesthetic agent supply is allowed or prevented, and a second apparatus contact (63) to indicate that this apparatus is configured to supply anesthetic agent.
