The utility model relates to a single-serial-port communication circuit for communicating different signals, and belongs to the field of communication circuits. According to the single-serial-port communication circuit for communicating different signals, a serial port of a singlechip is used, the connected relation of different communication signal converting chips in a circuit is changed over by using a double-channel one-from-four analog switch U2 and a double-channel one-from-four analog switch U5 and controlling coding wires of the analog switch U2 and the analog switch U5 by software, and a singlechip system has functions of the different communication signals, and can be communicated with different communication signal devices. By the single-serial-port communication circuit for communicating different signals, the single serial port can be communicated with the different signal devices in a time sharing manner. Moreover, the communication circuit is expandable; production and processing on communication wires by which the communication circuit is communicated with communication devices are eliminated; the hardware control ability of the singlechip is sufficiently utilized; and functions of the software of the singlechip are sufficiently fulfilled and are easy to implement. The cost and the workload are reduced; the single-serial-port communication circuit is compact in structure and reliable in communication; and the stability of the system is improved.