Panasonic KX-T7633 - Call Waiting and Announcement Features; Call Waiting Notification; Off Hook Call Announcement (OHCA); Whisper Off Hook Call Announcement

10.2. LCD CIRCUIT
LCD data are outputted from pin 57, 58, 59,10 and 12 of IC3 to LCD module.
IC8 is an inverter for a charge pump circuit which outputs the voltage necessary for LCD driving.
- 4.5V from -1.2V generated at IC8 as a reference to +3.3V of the
power supply voltage is pressurized four times in the LCD module
and used as LCD driving voltage(approx. 18V).
LCD contrast is set by electronic volume in the LCD module.
The type of the LCD module is distinguished by pin 62 of IC3.
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