Circuit Operations - Panasonic EASA-PHONE KX-T2355 Service Manual And Technical Manual

CIRCUIT OPERATIONS
is ON-> Q2 is OFF and Q1 is OFF. (break)
_ If port Pin 8is LOW
Q8 is OFF Q2 is ON—> Q1 is ON. (make)
Circuit Diagram ... See page 7
@ RINGER CIRCUIT
Circuit Operation:
The bell signal passes through C1 (R1)—> diode bridge, supplying power to pin 1 of IC2.
id "2iectinw wae Bell sensitivity adjustment |
AA GF fest g fi gens Bell frequency setting fH1, fH2
gy Cs) eta Gere Repeat frequency setting fL
fH1, fH2, fL are derived from the following formulas:
fH1 = : = §71Hz fl =
1.515 xR4xC4 | 1.234*R3xC3
=11.1Hz
R4 = 120k C6=0.0082nF R3 = 330k C3=0.22uF R2 = 10k
The following shows the waveform of the tone ringing IC output: