A field device adapter for wireless data transmission, having at least: - One adapter housing with a first end and a second end, wherein the first end has a first connecting element and a second connecting element for electrically connecting to the field device electronics of a field device, and the second end has a third connecting element and a fourth connecting element for electrically connecting a two-wire cable; - Adapter electronics arranged in the adapter housing, which connect the first connecting element to the third connecting element through a first electrical connecting cable, and the second connecting element to the fourth connecting element through a second electrical connecting cable, wherein the adapter electronics comprise a preferably unregulated or non-regulated first supply circuit integrated into the first connecting cable for providing a first supply voltage from a loop current flowing in the first connecting cable, and a preferably unregulated or non-regulated second supply circuit integrated into the second connecting cable for providing a second supply voltage from the loop current flowing in the second connecting cable, wherein the adapter electronics further comprise a HART modem, which is based on a HART protocol, which is connected to the second connecting cable at least via a tapping point arranged in the second connecting cable, and are adapted to tap a two-wire signal modulated onto the loop current and to translate it into a signal, preferably a UART signal, and/or to translate a supplied signal, preferably a UART signal, into a two-wire signal, and to modulate the translated two-wire signal onto the loop current via the tapping point, wherein the adapter electronics further comprise a radio module with an antenna for transmitting and/or receiving and are adapted to transmit the signal translated and supplied by the HART modem, preferably a UART signal, as a radio signal and/or to receive a radio signal which is to be translated into a two-wire signal by the HART modem and to supply it as a signal, preferably a UART signal, to the HART modem, wherein the adapter electronics are configured in such a way that the first supply circuit supplies the HART modem with the first supply voltage and the second supply circuit supplies the radio module with the second supply voltage, preferably independently of one another. - One adapter housing with a first end and a second end, wherein the first end has a first connecting element and a second connecting element for electrically connecting to the field device electronics of a field device, and the second end has a third connecting element and a fourth connecting element for electrically connecting a two-wire cable; - Adapter electronics arranged in the adapter housing, which connect the first connecting element to the third connecting element through a first electrical connecting cable, and the second connecting element to the fourth connecting element through a second electrical connecting cable, wherein the adapter electronics comprise a preferably unregulated or non-regulated first supply circuit integrated into the first connecting cable for providing a first supply voltage from a loop current flowing in the first connecting cable, and a preferably unregulated or non-regulated second supply circuit integrated into the second connecting cable for providing a second supply voltage from the loop current flowing in the second connecting cable, wherein the adapter electronics further comprise a HART modem, which is based on a HART protocol, which is connected to the second connecting cable at least via a tapping point arranged in the second connecting cable, and are adapted to tap a two-wire signal modulated onto the loop current and to translate it into a signal, preferably a UART signal, and/or to translate a supplied signal, preferably a UART signal, into a two-wire signal, and to modulate the translated two-wire signal onto the loop current via the tapping point, wherein the adapter electronics further comprise a radio module with an antenna for transmitting and/or receiving and are adapted to transmit the signal translated and supplied by the HART modem, preferably a UART signal, as a radio signal and/or to receive a radio signal which is to be translated into a two-wire signal by the HART modem and to supply it as a signal, preferably a UART signal, to the HART modem, wherein the adapter electronics are configured in such a way that the first supply circuit supplies the HART modem with the first supply voltage and the second supply circuit supplies the radio module with the second supply voltage, preferably independently of one another.