Panasonic KX-FLB758RU Service Manual page 169

7.3.4. RESET
RESET signal
The System Reset signal (RESETn) comes from the IC 604-K18pin, ´H´ level (3.3V) in normal times, while ´L´ (0V) at reset.
A built-in reset circuit inside IC 604 triggers a reset when the +5V power line voltage drop below 4.3V,or the 3.3V power line
voltage drop below 2.9V.
What to do when the system does not start up after the power is turned ON.
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KX-FLB758RU