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January 2005 © TOSHIBA TEC
e-STUDIO170F Circuit Description
7 - 61
SG/HK models
Fig.7-43
The line current detect circuit consists of the line current detection IC (IC1), ASIC (I/O port: IC38) on the
Main PBA, and other peripheral devices. It detects a dial tone and the hook status of the external tele-
phone from the current flowing through the line.
When a dial tone is input from the telephone line, current flows through the line. The line current detec-
tion IC sends the REVA and REVB to the ASIC as pulse signals. This allows a dial tone to be detected.
Signal Name
Type
Active
Description
Destination
REVA
I
-
Line current detect signal
ASIC
REVB
I
-
Current reverse line current detect signal
ASIC
CN10
Lb
R94
Line
REVA
REVB
19
4
20
1
2
8
7
19
20
36
37
NCU PBA
Main PBA
IC38
ASIC
(I/O port)
CN9
CN16
IC1
Line current
detection IC
Содержание ESTUDIO170F
Страница 1: ...SERVICE MANUAL PLAIN PAPER FACSIMILE e STUDIO170F File No SME04002900 R04102171300 TTEC Ver01_2005 05 ...
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Страница 192: ...e STUDIO170F Function Settings January 2005 TOSHIBA TEC 4 132 ...
Страница 214: ...e STUDIO170F Mechanical Description January 2005 TOSHIBA TEC 5 22 ...
Страница 308: ...e STUDIO170F Circuit Description January 2005 TOSHIBA TEC 7 78 ...
Страница 372: ...e STUDIO170F Removal Replacement Adjustment January 2005 TOSHIBA TEC 8 64 ...
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