An auxiliary channel transceiving circuit includes: a first node and a second node; a first voltage-dividing circuit for generating a first received signal according to a signal from the first node; a second voltage-dividing circuit for generating a second received signal according to a signal from the second node; a first receiver amplifying circuit for amplifying the first received signal to generate a first amplified signal; a second receiver amplifying circuit for amplifying the second received signal to generate a second amplified signal; a comparison circuit for comparing the first amplified signal with the second amplified signal to generate a received signal; a first transmitter amplifying circuit for generating a first output signal according to a transmitting signal; and a second transmitter amplifying circuit for generating a second output signal according to the transmitting signal. The auxiliary channel transceiving circuit is not required to cooperate with traditional capacitors.