The EM91850 are tone/pulse switchable dialer with Last Number Redail (LNB) and SAVE function, which are fabricate in CMOS technology with wide operating voltage for both tone and pulse mode. EM91850 consumes very low memory retention current in on hook state. The EM91850 provide necessary functions of telephone set for application in any environment, such as pulse dialing, tone (DTMF) dialing, handfree dialing. Beside this, hold , mute and redial function are provide for particular operation. In redial mode EM91850 can auto insert pause time for application in PABX system. EM91850 also have a special I/O pin - VAO can used tocontrol the receive volume amplify circuit.