Read Panasonic KX-TS2368CAW Service Manual online
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KX-TS2368CAW
4.2.
Circuit Operation
4.2.1.
Ringer Circuit
When the bell signal is input between telephone line, the signal are output at the speaker via the following path:
Tel line
R1 [R21] C1 [C21] D1 [D21] IC1 (1) [IC22 (1)] IC1 (8) [IC22 (8)] C5 [C35] T1 [T21] C625 Speaker
[ ] : in case of Line2
4.2.2.
Telephone Line Interface
4.2.2.1.
Circuit Operation
• On hook
Q101 is open, Q101 is connected as to cut DC loop current and cut the voice signal.
• Off hook (in case of Line 1)
In talk status, RLY output from IC801 (45) changes to low level, causing Q103, Q101 to turn on and resulting in a line loop.
Q101 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.
(Line 1) Tip
Q101 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.
(Line 1) Tip
POS101 D110 SW110 Q101 Q108 R124 D106 D110 (Line 1) Ring
• Pulse mode
A pulse signal that repeated switches between high and low logic is output from IC801 (44).
This switches the line loop on and off, generating the dial pulse signal.
This switches the line loop on and off, generating the dial pulse signal.
• The receiving signal flows: (in case of Line 1)
TEL line
POS101 SW110 Q101 C113 R125 C108 Q109 Q405 Q406 C414 VR402 CN401
CN402
Speaker (H/S)
• The transmission signal flows: (in case of Line 1)
Mic
VR401 Q421 Q424 C435 R437 Q108 SW110 POS101 Tel Line
4.2.3.
Tone Detect
This circuit is used to sense the status of the line (busy tone or dial tone) during Auto Redial.
4.2.3.1.
Circuit Operation
D110
Q101 C201 R201 R205 IC201 (5) IC201 (1) D202 R208 Q201 IC801 (50)
When the subscriber hangs-up, check the intermittent tone. If cycle tone is detected, the collector of Q201 goes to a low logic.
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