GENERAL DESCRIPTION
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.

FEATURES
• Volume add Control Function.
• One key Redial Function.
• Flash key is available and have multiple Flash time ( 600 ms, 300 ms, 100 ms ) can be selected.
• Auto Insert Pause Time.
• Tone/Pulse Switchable.
• Pulse mode fixed 10PPS.
• Pulse to tone ( P→T ) key is provided for PABX operation.
• Many options can be selected by R option.
    Mode ( Pulse, Tone )
    M/B ratio ( 40:60 ; 33:66 )
    Auto insert pause time ( enable ; disable )
• One set 32 digits SAVE function.
• One set 32 digits LNB redial function.
• Mixed and cascaded dialing.
• Hold and Mute function.
• Hand Free dialing.
• Tone duration and inter -tone pause are fixed at 90 ms.
• Flash pause time are fixed at 600 ms.
• Pulse to Tone pause time are fixed at 3.6sec.
• Uses 3.579545 MHz crystal or ceramic resonator (with built-in capacitor, no need extra capacitor).
• Package in DIP 16.

Total System
• Operating voltage : 2.0V ~ 5.5V
• Operating current : Tone mode 0.3 mA (typical) ~ 0.5 mA
                                 Pulse mode 0.15 mA (typical) ~ 0.2 mA
• Standby current : 0.01 uA ( typical ) 0.1 uA (max.)
• Use single clock 3.579545 MHz crystal