Panasonic KX-NT553RU-B / KX-NT556RU-B Service Manual ▷ View online
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KX-NT553RU/KX-NT553RU-B/KX-NT556RU/KX-NT556RU-B
4.2.3.
Ethernet Circuit
The PHY IC (IC401) is used for the Ethernet interface.
It is connected from IC401 to the Ethernet port (JK401) through a transformer and so is isolated.
Also, LAN port (JK402) gets power from the Ethernet line for PoE (Power over Ethernet) as shown below.
It is connected between IC401 and the BBIC (IC501) by high-speed bus called MII (Media Independent Interface) bus operating
with 25MHz.
It is connected from IC401 to the Ethernet port (JK401) through a transformer and so is isolated.
Also, LAN port (JK402) gets power from the Ethernet line for PoE (Power over Ethernet) as shown below.
It is connected between IC401 and the BBIC (IC501) by high-speed bus called MII (Media Independent Interface) bus operating
with 25MHz.
4.2.4.
Analog Circuit
1. Speaker phone call
Transmitting signal is input from microphone (differential amplifier circuit)
input to IC502-L19, M19 A/D conversion, Gain
adjustment and echo cancel by a built-in DSP of IC502.
Receiving signal input from IP Line
Receiving signal input from IP Line
Gain adjustment and D/A conversion by DSP of IC502 output from IC502-V18, V19
output to Speaker.
IC502
SPP
SPM
DGND
DGND
DGND
DGND
C128
C114
C115
D103
D104
CL-SPP
CL-SPM
R122
R134
C108
DGND
DGND
C121
C110
DGND
C111
DGND
L102
NC
L103
C124
L109
L107
C129
R104
R109
C117
R106
C116
C119
C120
R105
R110
C109
R107
AGND
AGND
AGND
AGND
MICP
MICM
R102
R103 0
R123
AGND
MICBIAS
C149
C112
C113
C105
C106
D101
D102
CL-MICP
CL-MICM
AGND
AGND AGND
AGND
AGND
V19
V18
L19
M19
Speaker
Mic
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KX-NT553RU/KX-NT553RU-B/KX-NT556RU/KX-NT556RU-B
2. Handset call
Transmitting signal is input from handset microphone
input to IC502-K18, K19 A/D conversion, Gain adjustment by a
built-in DSP of IC502.
Receiving signal input from IP Line
Receiving signal input from IP Line
Gain adjustment and D/A conversion by DSP of IC502 output from IC502-V18, V19
output to handset speaker.
3. Headset Call
Transmitting signal is input from headset microphone
input to IC502-N15 A/D conversion, Gain adjustment by a built-in
DSP of IC502.
Receiving signal input from IP Line
Receiving signal input from IP Line
Gain adjustment and D/A conversion by DSP of IC502 output from IC502-L17 out-
put to headset speaker.
IC502
Handset
R116
C101
C103
C145
R114
C142
R112
C127
C138
R119
C141
R120
3.3k
C139
R115
AGND
AGND
AGND
AGND
AGND
AGND
AGND
AGND
R108
R111
AGND
MICBIAS
R131
C150
C125
C126
C133
C134
C102
C118
C122
D106
D107
D108
D109
JK102
2
3
4
5
L104
L105
AGND
AGND
AGND
AGND
AGND
M18
M17
K18
K19
IC502 CN205
Handset
R118
MICBIAS
C137
HEADSET-OUT
C136
L108
R113
C143
HEADSET-IN
AGND
AGND
AGND
AGND
AGND
R126
C205
C130
C144
HEADSET_IN
001:4E
HEADSET_OUT
001:4E
L106
N15
L17
C221
C217
CL204
CL203
CL206
CL205
C218
JK202
1
4
2
3
5
C226
C205
AG_PAD
L210
L209
L208
AG
AG
AG
C207
R223
HEADGND
HEADGND
HEADGND
HEADGND
HEADGND
D247
1
2
D246
1
2
D245
1
2
12
14
Handset
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KX-NT553RU/KX-NT553RU-B/KX-NT556RU/KX-NT556RU-B
4.2.5.
ASIC (IC205)
IC205 controls KEY, LED, EHS and Headset-detect.
An operating clock is provided by IC502 and a reset signal from the IC502 starts either reset or normal operating.(L(0V):RESET)
The IC205 and IC502 are connected by an I2C communication.
IC502 checks the presence of IC205 by getting the signal from IC205.
An operating clock is provided by IC502 and a reset signal from the IC502 starts either reset or normal operating.(L(0V):RESET)
The IC205 and IC502 are connected by an I2C communication.
IC502 checks the presence of IC205 by getting the signal from IC205.
LED and KEY Timing chart
The LED control and the KEY control use the same strobe(STB) signal.
Therefore, the LED control and the KEY control are alternately executed.
The timing chart is as shown in the following .
Therefore, the LED control and the KEY control are alternately executed.
The timing chart is as shown in the following .
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KX-NT553RU/KX-NT553RU-B/KX-NT556RU/KX-NT556RU-B
4.2.6.
Key Circuit
The key data is under the matrix control by IC205.
The key information output from LED_STB is input into KEYIN, when the key is pressed.
The key information output from LED_STB is input into KEYIN, when the key is pressed.
The HOOK key is independent from Key Scan Matrix and taken into the port singularly.
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