The KK91210E is a single-chip, silicon gate, CMOS integrated circuit with an on-chip oscillator for a 3.58 MHz crystal or ceramic resonator. It provides dialing pulse (DP) or dual tone multi-frequency (DTMF) dialing. A standard 4x4 matrix keyboard can be used to support either DP or DTMF modes. Up to 32 digits can be saved in the on-chip RAM for reading. In the DTMF mode, minimum tone duration and minimum intertone pause are provided for rapid dialing. Maximum tone duration is dependent upon the key depression time in manual dialing. One touch redial operation