Read Panasonic KX-TS2361UAW (serv.man4) Service Manual online
8 CIRCUIT OPERATION
8.1. Bell Ringer Circuit
When the bell signal is input between T/R, the signal are outputted at the speaker via the following path:
TEL line
TEL line
→
R1/C1
→
IC2 (pin 8)
→
IC2 (pin 5)
→
R3
→
C37
→
SW3
→
Ringer
8.2. Line Interface
In talk status, SW1 become ON and Q22, Q2 base changes to high level, causing Q1, Q22, Q2 to turn on and resulting in a
line loop. The loop current flows from D1(+)
line loop. The loop current flows from D1(+)
→
Q1
→
Q3
→
R14
→
D6 in that order, A pulse signal that repeated switches
between high and low logic is output from pin 10 of the IC1. This switches the line loop on and off, generating the dial pulse
signal.
signal.
8.3. MODULE BLOCK DIAGRAM
8.3.1. Telephone Line Interface
8.3.1.1. Circuit operation
·
On hook
Q1 is open, Q1 is connected as to cut DC loop current and cut the voice signal.
·
Off hook
Q1 turns on thus providing an off-hook condition (active DC current flow through the circuit) and the following signal flow is for
the DC loop current.
T
the DC loop current.
T
→
D1
→
Q1
→
Q3
→
R14
→
D6
→
D1
→
R
·
The receiving signal flows:
TEL line
→
Q1
→
C12
→
R15
→
Q4
→
Q6
→
Q7
→
H/S SP
·
The transmission signal flows
MIC
→
Q9
→
R38
→
C23
→
Q3
→
TEL Line
14
KX-TS2361UAW
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