An interface circuit, wherein the interface circuit is configured to perform data transmission with a first device not comprised in the interface circuit by using a data transmission apparatus not comprised in the interface circuit, and the interface circuit comprises an interface indication end and a data transmission end; the interface circuit is configured to obtain indication information from an indicator of the data transmission apparatus through the interface indication end, wherein the indication information is configured to indicate a data transmission interface protocol of the first device; the interface circuit is configured to transmit data to the first device through the data transmission end based on the data transmission interface protocol of the first device indicated by the indication information; the interface circuit further comprises a plurality of interface controllers (01, 02, 03, 04), a multiplexer, a port physical layer, and a mode controller, wherein the plurality of interface controllers (01, 02, 03, 04) are respectively coupled to a plurality of input ends of the multiplexer; an output end of the multiplexer is coupled to a first end of the port physical layer; a second end of the port physical layer is coupled to the data transmission end of the interface circuit; an input end of the mode controller is coupled to the interface indication end of the interface circuit, an output end of the mode controller is coupled to a first control end of the multiplexer, and the mode controller is configured to control, based on the indication information, the multiplexer to connect a first interface controller (01, 02, 03, 04) in the plurality of interface controllers (01, 02, 03, 04) to the port physical layer, and the output end of the mode controller is also coupled to a first control end of the port physical layer; the port physical layer comprises a transmitter, and the transmitter is configured to transmit data to the first device by using the data transmission apparatus; the interface circuit further comprises a capacitor (C T1), a second resistor (R T1), and a first switch (K T1), wherein a first end of the capacitor (C T1) is coupled to an output end of the transmitter, and a second end of the capacitor (C T1) and one end of the second resistor (R T1) are coupled to the data transmission end of the interface circuit; and the other end of the second resistor (R T1) is coupled to the ground end through the first switch (K T1). the interface circuit is configured to obtain indication information from an indicator of the data transmission apparatus through the interface indication end, wherein the indication information is configured to indicate a data transmission interface protocol of the first device; the interface circuit is configured to transmit data to the first device through the data transmission end based on the data transmission interface protocol of the first device indicated by the indication information; the interface circuit further comprises a plurality of interface controllers (01, 02, 03, 04), a multiplexer, a port physical layer, and a mode controller, wherein the plurality of interface controllers (01, 02, 03, 04) are respectively coupled to a plurality of input ends of the multiplexer; an output end of the multiplexer is coupled to a first end of the port physical layer; a second end of the port physical layer is coupled to the data transmission end of the interface circuit; an input end of the mode controller is coupled to the interface indication end of the interface circuit, an output end of the mode controller is coupled to a first control end of the multiplexer, and the mode controller is configured to control, based on the indication information, the multiplexer to connect a first interface controller (01, 02, 03, 04) in the plurality of interface controllers (01, 02, 03, 04) to the port physical layer, and the output end of the mode controller is also coupled to a first control end of the port physical layer; the port physical layer comprises a transmitter, and the transmitter is configured to transmit data to the first device by using the data transmission apparatus; the interface circuit further comprises a capacitor (C T1), a second resistor (R T1), and a first switch (K T1), wherein a first end of the capacitor (C T1) is coupled to an output end of the transmitter, and a second end of the capacitor (C T1) and one end of the second resistor (R T1) are coupled to the data transmission end of the interface circuit; and the other end of the second resistor (R T1) is coupled to the ground end through the first switch (K T1).