Panasonic KX-TC1811B Service Manual ▷ View online
11.11. Greeting Recording Circuit
Circuit Operation:
MIC
MIC
→
C724
→
C725
→
C726
→
R726
→
pin 47 of IC501.
11.12. Greeting Play Back Circuit
Circuit Operation:
pin36 of IC501
pin36 of IC501
→
R431
→
C432
→
C433
→
Telephone Line.
45
KX-TC1811B
11.13. ICM Recording Circuit
Circuit Operation:
Telephone Line
Telephone Line
→
Q131
→
C463
→
R448
→
C442
→
R464
→
C441
→
pin 32 and 33 of IC501.
11.14. ICM Play Circuit
Circuit Operation:
pins 32 and 33 of IC501
pins 32 and 33 of IC501
→
Speaker.
46
KX-TC1811B
11.15. Telephone Line Interface
Circuit Operation:
l
ANSWER
In the idle mode, Q121 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:
T
and Ring (R) leads (When the telephone rings), the AC ring voltage is transferred as follows:
T
→
L101
→
R103
→
C103
→
Q101
→
IC501 pin 64.
When the CPU (DSP) detects a ring signal, Q121 turns on, thus providing an off-hook condition (active DC current flow through the
circuit) and the following signal flow is for the voice signal.
T
circuit) and the following signal flow is for the voice signal.
T
→
D101
→
Q121
→
Q131
→
R138
→
C140
→
D101
→
L102
→
PO101
→
R
l
ON HOOK
Q121 is open, Q121 is connected as to cut the DC loop current and to cut the voice signal. The unit is consequently in an on-hook
condition.
condition.
l
SPECIFICATIONS
In the on-hook state (idle), the current flows between the telephone line and the unit is as follows:
T
T
→
L101
→
R103
→
C103
→
R106
→
C104
→
R104
→
L102
→
PO101
→
R.
The DC component is blocked by C103, C104: thereby providing an on-hook condition.
The AC interface impedance is over 47 k
The AC interface impedance is over 47 k
Ω
; thus, satisfying the telephone company requirements.
11.16. Intercom Mode
1. When the base unit LOCATOR/INTERCOM button is pressed, a call monitor signal (intercom sound) is output from pins 32 and
33 of IC501. Thus a monitor tone is heard from the speaker.
2. At the same time, flashing of the IN USE/CHARGE (LED541) is obtained from pin 65 of IC501. This status is called "Intercom
stand-by".
3. The receiving signal flows:
RF
→
pin 32 and 33 of IC501
→
SP
4. The transmission signal flows:
MIC
→
C724
→
C725
→
C726
→
R726
→
pin 47 of IC501
→
RF
47
KX-TC1811B
11.17. Initializing Circuit
Function:
This circuit is used for to initialize the microcomputer when it incorporates an AC adaptor.
This circuit is used for to initialize the microcomputer when it incorporates an AC adaptor.
Circuit Operation:
When the AC Adaptor is inserted into the unit, then the voltage is shifted by IC301, D306 and power is supplied to the DSP.
The set can operate beyond point A in the circuit voltage diagram.
When the AC Adaptor is inserted into the unit, then the voltage is shifted by IC301, D306 and power is supplied to the DSP.
The set can operate beyond point A in the circuit voltage diagram.
48
KX-TC1811B
Click on the first or last page to see other KX-TC1811B service manuals if exist.