A hearing aid comprising: a first module comprising a behind-the-ear housing and accommodating first circuitry; a second module comprising an in-the-ear housing and accommodating second circuitry; and an interconnecting member configured for interconnecting the first circuitry with the second circuitry; wherein the second circuitry comprises a memory for storing data relating to a configuration of the second module including the second circuitry, and data communication circuitry configured for transmission of the data relating to the configuration from the memory to the first circuitry, and a power supply that is powered from the first circuitry and comprises a rectifier and a capacitor, characterized in that i) the capacitor is charged through the rectifier by a high frequency signal from the first circuitry, whereby the high frequency signal is transmitted during boot of the first circuitry at power up of the hearing aid, ii) the interconnecting member accommodates three conductors (44, 46, 50), whereby a first conductor and a second conductor of these three conductors are configured to transmit a hearing loss compensated signal to a receiver of the hearing aid, iii) a third conductor of the three conductors is configured to transmit the high frequency signal and the data relating to the configuration of the second module. a first module comprising a behind-the-ear housing and accommodating first circuitry; a second module comprising an in-the-ear housing and accommodating second circuitry; and an interconnecting member configured for interconnecting the first circuitry with the second circuitry; wherein the second circuitry comprises a memory for storing data relating to a configuration of the second module including the second circuitry, and data communication circuitry configured for transmission of the data relating to the configuration from the memory to the first circuitry, and a power supply that is powered from the first circuitry and comprises a rectifier and a capacitor, a memory for storing data relating to a configuration of the second module including the second circuitry, and data communication circuitry configured for transmission of the data relating to the configuration from the memory to the first circuitry, and a power supply that is powered from the first circuitry and comprises a rectifier and a capacitor, characterized in that i) the capacitor is charged through the rectifier by a high frequency signal from the first circuitry, whereby the high frequency signal is transmitted during boot of the first circuitry at power up of the hearing aid, ii) the interconnecting member accommodates three conductors (44, 46, 50), whereby a first conductor and a second conductor of these three conductors are configured to transmit a hearing loss compensated signal to a receiver of the hearing aid, iii) a third conductor of the three conductors is configured to transmit the high frequency signal and the data relating to the configuration of the second module. i) the capacitor is charged through the rectifier by a high frequency signal from the first circuitry, whereby the high frequency signal is transmitted during boot of the first circuitry at power up of the hearing aid, ii) the interconnecting member accommodates three conductors (44, 46, 50), whereby a first conductor and a second conductor of these three conductors are configured to transmit a hearing loss compensated signal to a receiver of the hearing aid, iii) a third conductor of the three conductors is configured to transmit the high frequency signal and the data relating to the configuration of the second module.