Panasonic KX-T7735UA / KX-T7735UA-B (serv.man3) Service Manual / Supplement ▷ View online
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KX-T7735UA/KX-T7735UA-B
1.7.2.
LED CIRCUIT
Change from the Original Service Manual Section 8.2.
Circuit Operation:
The LED executes dynamic lighting for the status indicators, and control is executed by the output ports P3_1, P3_6, P8_5~6,
P4_5, P1_1~7.
P4_5, P1_1~7.
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KX-T7735UA/KX-T7735UA-B
1.7.3.
DATA COMMUNICATION CIRCUIT
Change from the Original Service Manual Section 8.3.
Function:
The data communication circuit serves the following functions:
Information exchanger between the PBX and proprietary telephone, key input information as well as data for the LED control, LCD
control, etc. This information is continuously exchanged at all times.
Information exchanger between the PBX and proprietary telephone, key input information as well as data for the LED control, LCD
control, etc. This information is continuously exchanged at all times.
Circuit Operation:
When the proprietary telephone receives an IRQ signal from the PBX and after sending the key input information (19 pulses) to the
PBX and receiving data (47 pulses) for the LED control, etc., the proprietary telephone will return to the PBX an acknowledge sig-
nal.
PBX and receiving data (47 pulses) for the LED control, etc., the proprietary telephone will return to the PBX an acknowledge sig-
nal.
1) Reception
The data from the PBX is received via the H and L lines along the path shown below.
H, L Line
→ D2 → T2 → R106 → Q102 → IC9 → IC1 Pin 19
2) Transmission
The data to the proprietary telephone is transmitted along the following path.
IC1 Pin 16
→ Q101 → T2 → D2 → H, L Line
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KX-T7735UA/KX-T7735UA-B
1.7.4.
TONE GENERATION CIRCUIT
Change from the Original Service Manual Section 8.4.
Function:
This circuit generates all system tones including COL, extension, busy, DTMF signals and key in confirmation tones during the
power failure mode and is comprised of IC1(DTMF Generator) and IC5 (Analog Switch).
power failure mode and is comprised of IC1(DTMF Generator) and IC5 (Analog Switch).
Circuit Operation:
For an output of a single row tone, the row terminal and the each column terminals intersecting with it are required to be brought a
low state. For a dual tone output, one row terminal and one column terminal are brought to low state.
low state. For a dual tone output, one row terminal and one column terminal are brought to low state.
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KX-T7735UA/KX-T7735UA-B
1.7.5.
HANDSET CIRCUIT
Change from the Original Service Manual Section 8.5.
1) Transmission Signal Path
The input signal for the handset microphone is sent through the telephone line via the following path:
Handset MIC(JK2)
Handset MIC(JK2)
→ JK3 → C24 → R26 → C34 → Q5 → C21 → R21 → Q3 → C4 → T1 → C3 → Q1 → D1 → Telephone Line
2) Reception Signal Path
The input signal from the telephone line is sent to the receiver through the following path:
Telephone Line
Telephone Line
→ D1 → Q1 → C3 → T1 → C4 → Q3 → R10 → C8 → R12 → Q4 → C26 → R32 → IC10 → C32 → R34 → C27 →
R208
→ Q8 → C31 → JK3 → JK2 → Handset Speaker
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