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9
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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