The HART protocol superimposes audio digital signals on 4~20 mA analog signals. The digital signal amplitude is 0.5 mA and the data rate reaches 1200 b/s. 1200 Hz represents logic "1" and 2200 Hz represents logic "0". Enables two-way digital communication. HART communication has the characteristics of simultaneous point-to-point 4 ~ 20 mA analog and digital communication, multi-station communication methods, and multiple transmissions.The HT1200M is compatible with the SYM20C15 and HT20C15 and with ON OnSemi's A5191HRT and HT2015.