The invention discloses a communication circuit compatible with various signal sources and a signal transmission device. The communication circuit comprises a signal transmission port, a power conversion module and a main control module, the signal transmission port communicates with an external communication device, and a communication signal outputted by the communication device is accessed intothe signal transmission port; the power conversion module converts a direct current power supply into a voltage-stabilized power supply, and the voltage-stabilized power supply charges the communication equipment, so that the communication equipment is in a rated working state. The main control module receives and identifies a communication signal, performs signal communication with communicationequipment according to the communication signal, and transmits the control data to the communication equipment. The communication circuit in the embodiment of the invention can be compatible with andidentify different types of signal sources, and the application range is wide. The communication circuit can realize a corresponding circuit function according to the communication signal, and the communication cost and the application cost of the communication equipment are reduced.