Read Panasonic KX-TG6711RUB / KX-TG6711RUM / KX-TG6712RUM / KX-TG6721RUB / KX-TG6721RUS / KX-TG6722RUB / KX-TG6711CAB / KX-TG6711CAM / KX-TG6721CAB / KX-TG6721CAM / KX-TG6722CAB / KX-TG6711UAB / KX-TG6711UAM / KX-TG6712UAB / KX-TG6721UAB / KX-TGA671RUB / KX-TGA671RUS Service Manual online
12
KX-TG6711RU/KX-TG6712RU/KX-TG6721RU/KX-TG6722RU/KX-TG6711CA/KX-TG6712CA/KX-TG6721CA/KX-TG6722CA/KX-TG6711UA/KX-TG6712UA/KX-TG672IUA//KX-TGA671EX
4.4.4.
Telephone Line Interface
Telephone Line Interface Circuit:
Function
Function
• Bell signal detection
• ON/OFF hook and pulse dial circuit
• Side tone circuit
• ON/OFF hook and pulse dial circuit
• Side tone circuit
Bell signal detection and OFF HOOK circuit:
In the idle mode, Q141 is open to cut the DC loop current and decrease the ring load. When ring voltage appears at the Tip (T)
and Ring (R) leads (When the telephone rings), the AC ring voltage is transferred as follows:
R
and Ring (R) leads (When the telephone rings), the AC ring voltage is transferred as follows:
R
→ P101 → R111 → C111 → Q111 → BBIC pin 5
When the CPU (BBIC) detects a ring signal, Q141 turns on, thus providing an off-hook condition (active DC current flow
throughthe circuit). Following signal flow is the DC current flow.
T
throughthe circuit). Following signal flow is the DC current flow.
T
→ D101 → Q141 → Q161 → R163 → R167 → R168 → D101 → P101 → R
ON HOOK Circuit:
Q141 is open, Q141 is connected as to cut the DC loop current and to cut the voice signal. The unit is consequently in an on-
hook condition.
hook condition.
Pulse Dial Circuit:
Pin 6 of BBIC turns Q141 ON/OFF to make the pulse dialing.
Side Tone Circuit:
Basically this circuit prevents the TX signal from feeding back to RX signal. As for this unit, TX signal feed back from Q161 is
canceled by the canceller circuit of BBIC.
canceled by the canceller circuit of BBIC.
4.4.5.
Power Supply Circuit
The power supply voltage from AC adaptor is converted to VBAT (3.0V) in DC/DC converter circuit. And +3.0V for peripherals
and analog part is insulated from VBAT by Doubler of BBIC.
Circuit Operation:
and analog part is insulated from VBAT by Doubler of BBIC.
Circuit Operation:
5.5V
VBAT
RSTN(Reset)
pin 54
VBAT
pin 10
pin 57
pin 9
pin 15
IC501
Q301, IC301,
L301, C341
L301, C341
IC601
BBIC
DOUBLER OUT
For peripherals
For peripherals
VDDC (1.2V)
AC Adaptor
3.0V
DC/DC
CONVERTER
CIRCUIT
FLASH
IC611
EEPROM
+3.0V
STM/CKM
Receive
Amp.
RF Part
LCD BLT
ANS LED
MSG LED
Startmonitor
(IC501 57pin)
VDDC (1.2 V)
VBAT
Reset (RSTN)
(IC501_54 pin)
(IC501_54 pin)
BBIC chip initialize
(CKM/STM)
LCD
(TAM COUNTER)
Click on the first or last page to see other KX-TG6711RUB / KX-TG6711RUM / KX-TG6712RUM / KX-TG6721RUB / KX-TG6721RUS / KX-TG6722RUB / KX-TG6711CAB / KX-TG6711CAM / KX-TG6721CAB / KX-TG6721CAM / KX-TG6722CAB / KX-TG6711UAB / KX-TG6711UAM / KX-TG6712UAB / KX-TG6721UAB / KX-TGA671RUB / KX-TGA671RUS service manuals if exist.