Panasonic KX-T7730UA Service Manual ▷ View online
9 CIRCUIT OPERATIONS
9.1. KEY INPUT CONTROL CIRCUIT
Sequential input information is executed by dynamic scanning.
The ports R20~R23, R30, R31 of IC1 are brought to high status consecutively.
If a key is pressed, the key-in information input is executed by ports R00~R03, R10~R13.
The ports R20~R23, R30, R31 of IC1 are brought to high status consecutively.
If a key is pressed, the key-in information input is executed by ports R00~R03, R10~R13.
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KX-T7730UA
9.2. LED CIRCUIT
Circuit Operation:
The LED executes dynamic lighting for the status indicators, and control is executed by the output ports R20~R23, R60~R63,
R70~R73.
The LED executes dynamic lighting for the status indicators, and control is executed by the output ports R20~R23, R60~R63,
R70~R73.
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9.3. DATA COMMUNICATION CIRCUIT
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.
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.
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
signal.
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
signal.
1) Reception
The data from the PBX is received via the H and L lines along the path shown below.
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 → IC2 → IC1 Pin 18
2) Transmission
The data to the proprietary telephone is transmitted along the following path.
The data to the proprietary telephone is transmitted along the following path.
IC1 Pin 16
→ IC2 → Q101 → T2 → D2 → H, L Line
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9.4. TONE GENERATION CIRCUIT
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).
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).
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.
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.
CONDITION
IC1 pin52
IC5 SWA
IC1 pin53
IC5 SWB
IC1 pin54
IC5 SWC
IC1 pin55
IC5 SWD
Ringing
L
OFF
L
OFF
L
OFF
H
ON
Call Waiting
L
OFF
L
OFF
H
ON
L
OFF
Tone Dial (Handset)
H
ON
H
ON
L
OFF
L
OFF
Tone Dial (Speakerphone)
H
ON
L
OFF
H
ON
L
OFF
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