Abstract: Based on the requirements of developing a new meter system,improvements has been made to the communication interface which was previously used on M-BUS slave node.The error rate is reduced by adding Schmitt trigger at the receiving end,and by changing the current modulation mode on the sending end to voltage modulation mode,the circuit becomes easier to implement.Currently this interface has been successfully applied to a slave chips,enabling 300~9600bps rates of communication.With the 0.35μm technology of 1st-silicon,the circuit is designed and simulated by Cadence Spectre and the simulation result is presented.