The IN9151-3 pulse dialer is a monolithic CMOS integrated circuit which converts pushbutton inputs to a series of pulses suitable for telephone dialing. It is intended to replace mechanical telephone dialers and can operate directly from telephone lines. CMOS technology is used to produced this device, resulting in very low power requirements and high noise immunity. The IN9151-3 can be easily interfaced with a variety of telephones, requiring only a minimal number of external components.

• Direct telephone line operation
• 4 x 3 matrix keyboard interface
• Supply voltage range of 2.0 to 5.5 volts
• Inexpensive RC oscillator
• Low power standby mode for redialing
• 22-digit redial memory
• Redial with either * or # key
• Dialer reset for line power breaks > 200 ms
• Selectable make/break ratio
• High speed test capacity