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January 2005 © TOSHIBA TEC
e-STUDIO170F Circuit Description
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7.4
NCU PBA
This section describes the function of each circuit on the NCU PBA.
The NCU PBA consists of the transformer, relay, analog switch, and other peripheral devices. It controls
switching the line path, generates dial pulses, detects line current, detects a ring signal, and monitors
the line.
The NCU PBA is connected to CN16 on the Main PBA.
US/CA models, SG/HK models
Fig.7-35
CN10
CN9
CN11
CN8
AG
0
1
0
1
DC
consumption
circuit
Ring signal
detection
circuit
IC53
IC53
IC52
IC52
IC51
Analog
switch
CNG signal
detection
circuit
NCU PBA
T1
HS1
HS2
b2
a2
HOOK
CML
ATT3DB
ANSDET
TXOUT
RXIN
REVB
REVA
CI
Lb
La
Line
External
TEL
TEL PBA
(Handset)
Main PBA
Dial pulse
generation
circuit
LD
-
DB1
+
~
~
RLY2
CML relay
Line current
detection
circuit
Summary of Contents for ESTUDIO170F
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Page 192: ...e STUDIO170F Function Settings January 2005 TOSHIBA TEC 4 132 ...
Page 214: ...e STUDIO170F Mechanical Description January 2005 TOSHIBA TEC 5 22 ...
Page 308: ...e STUDIO170F Circuit Description January 2005 TOSHIBA TEC 7 78 ...
Page 372: ...e STUDIO170F Removal Replacement Adjustment January 2005 TOSHIBA TEC 8 64 ...
Page 490: ...e STUDIO170F Appendix January 2005 TOSHIBA TEC 12 8 ...
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