Two bus transmission device

The utility model discloses a two bus transmission device, include: first bus, second bus, switchboard and at least one terminal, wherein, the switchboard includes that first time sign indicating number detection circuitry, second return sign indicating number detection circuitry, send out code spraying control, a switch circuit, the 2nd switch circuit, DC power supply, first electric capacity, switchboard transformer and switchboard audio processing circuit, the terminal includes terminal decode / return sign indicating number a circuit, terminal supply circuit, terminal transformer and terminal audio processing circuit. Transmit after first single -ended audio signal that the switchboard transformer sent switchboard audio processing circuit converts first difference signal into, transmit after the single -ended audio signal of second that the terminal transformer sent terminal audio processing circuit converts the second differential signal into to realize that the switchboard arrives the audio signal trans