According to an aspect, an apparatus comprises an integrated circuit and a memory circuit to process input signals obtained from a user according to a plurality of physiologic monitoring uses, and a physiologic monitoring sensor circuit, including at least one physiologic sensor and physiologic signal amplification and filtering circuitry, applied to the users skin by coupling physiologic signals from the users skin, to receive physiologic signals received by the coupling, and to amplify and filter the received physiologic signals for processing by the integrated circuit and therefrom measure a plurality of physiologic parameters of the user according to the physiologic monitoring uses. The apparatus comprises an external removable circuit to enable additional physiological monitoring uses, and verification and activation circuitry to receive initialization data from the external removable circuit and configure the integrated circuit and the physiologic monitoring sensor circuit to provide at least one additional physiologic parameter.
