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22.3. Ringer Circuit
If the ringer volume is set to low and an alarm tone is output from 51 pin, IC140 BBIC and input to Q103. Then Q107 is turned off.
If the ringer volume is set to high, Q107 turns on and results in a louder beep tone.
If the ringer volume is set to high, Q107 turns on and results in a louder beep tone.
22.4. CLOCK Circuit
This is the CLOCK oscillator circuit (VCO) consisting of the crystal oscillator X101 of 21.4 MHz. CLOCK sends the signal to pin 73
of IC140 (BBIC) and RF unit.The frequency of the CLOCK is adjusted (AFC) by pin 85 of IC140 (XTALDAC) to keep the link with
the base unit. To reduce the current consumption on sleeping, pin 71 of IC140 (OSCENA) stops the power supply.
of IC140 (BBIC) and RF unit.The frequency of the CLOCK is adjusted (AFC) by pin 85 of IC140 (XTALDAC) to keep the link with
the base unit. To reduce the current consumption on sleeping, pin 71 of IC140 (OSCENA) stops the power supply.
22.5. Reception Signal Circuit
The received signal from the base unit is output from pins 95 (AON) and 94 (AOP) of IC140 (BBIC) as the voice signal. AON is the
inverse output of AOP, and the speaker is driven by AON and AOP. CN101 is the headphone jack. When the headphone is
connected to this jack, the output to the speaker of the handset is cut and the voice signal is output to the headphone only.
inverse output of AOP, and the speaker is driven by AON and AOP. CN101 is the headphone jack. When the headphone is
connected to this jack, the output to the speaker of the handset is cut and the voice signal is output to the headphone only.
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KX-TC1800B
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