A circuit, comprising: a coaxial cable interface; a data module configured to receive or output a data signal; a power module configured to receive or output a power signal; a power signal transmission branch electrically coupled between the coaxial cable interface and the power module, wherein the power signal transmission branch includes an inductor that allows the power signal to pass; and a data signal transmission branch electrically coupled between the coaxial cable interface and the data module, characterised in that: the data signal transmission branch includes a capacitor that allows the data signal to pass, a resistor, a first electrical surge protection circuit configured to release a surge current on the data signal transmission branch, and a second electrical surge protection circuit, and the first electrical surge protection circuit includes a first protection device and a gas discharge tube that are connected in series; a common branch electrically coupled between the coaxial cable interface and a connection node between the power signal transmission branch and the data signal transmission branch; and a fourth electrical surge protection circuit configured to release an electrical surge on the common branch, one end of the fourth electrical surge protection circuit being coupled to the common branch, and another end being coupled to the ground, wherein the data module is coupled to the coaxial cable interface via the second electrical surge protection circuit, the resistor, the first electrical surge protection circuit, and the capacitor sequentially. a coaxial cable interface; a data module configured to receive or output a data signal; a power module configured to receive or output a power signal; a power signal transmission branch electrically coupled between the coaxial cable interface and the power module, wherein the power signal transmission branch includes an inductor that allows the power signal to pass; and a data signal transmission branch electrically coupled between the coaxial cable interface and the data module, characterised in that: the data signal transmission branch includes a capacitor that allows the data signal to pass, a resistor, a first electrical surge protection circuit configured to release a surge current on the data signal transmission branch, and a second electrical surge protection circuit, and the first electrical surge protection circuit includes a first protection device and a gas discharge tube that are connected in series; a common branch electrically coupled between the coaxial cable interface and a connection node between the power signal transmission branch and the data signal transmission branch; and a fourth electrical surge protection circuit configured to release an electrical surge on the common branch, one end of the fourth electrical surge protection circuit being coupled to the common branch, and another end being coupled to the ground, wherein the data module is coupled to the coaxial cable interface via the second electrical surge protection circuit, the resistor, the first electrical surge protection circuit, and the capacitor sequentially. the data signal transmission branch includes a capacitor that allows the data signal to pass, a resistor, a first electrical surge protection circuit configured to release a surge current on the data signal transmission branch, and a second electrical surge protection circuit, and the first electrical surge protection circuit includes a first protection device and a gas discharge tube that are connected in series; a common branch electrically coupled between the coaxial cable interface and a connection node between the power signal transmission branch and the data signal transmission branch; and a fourth electrical surge protection circuit configured to release an electrical surge on the common branch, one end of the fourth electrical surge protection circuit being coupled to the common branch, and another end being coupled to the ground, wherein the data module is coupled to the coaxial cable interface via the second electrical surge protection circuit, the resistor, the first electrical surge protection circuit, and the capacitor sequentially.