Panasonic KX-MB2571RU Service Manual ▷ View online
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KX-MB2571RU
6.3.4.
TEL Line Section
Composed of ITS circuit and NCU circuit.
6.3.4.1.
Description of Block Diagram in Analog Section
Function
The analog section works as an interface between the telephone line.
DAA control ITS circuit and NCU circuit.
DAA control signals are output from modem (IC203) through the DIB transformer (T100).
DAA control ITS circuit and NCU circuit.
DAA control signals are output from modem (IC203) through the DIB transformer (T100).
Circuit Operation
[NCU]: Network Control Unit the NCU comprises of the following; DC loop forming circuit to connect with the telephone line;
Switching circuit for other interconnected telephones; Bell detection circuit.
Refer to NCU Section (P.36) for the details.
Switching circuit for other interconnected telephones; Bell detection circuit.
Refer to NCU Section (P.36) for the details.
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KX-MB2571RU
6.3.4.2.
Block Diagram
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6.4.
NCU Section
NCU: (Network Control Unit)
Requires for connecting computers to public communication networks and send a dial signal to call the other party.
Requires for connecting computers to public communication networks and send a dial signal to call the other party.
6.4.1.
General
The NCU circuit is composed of the SmartDAA (IC101) and it's peripheral circuit and an EXT.TEL. Line relay (RLY100), Bell detec-
tion circuit. The SmartDAA implement the line interface characteristic such as DC mask, Return loss by modem(IC203) control. The
following is a brief explanation of each circuit.
tion circuit. The SmartDAA implement the line interface characteristic such as DC mask, Return loss by modem(IC203) control. The
following is a brief explanation of each circuit.
6.4.2.
EXT. TEL. Line Relay (RLY100)
1. Circuit Operation
Normally, this relay switches to the external telephone side and switches to the open side while OFF-HOOK.
IC203 (7) High Level
IC203 (7) High Level
Q203 ON RLY100 ON
6.4.3.
Bell Detection Circuit
1. Circuit Operation
The signal waveform for each point is indicated below. The signal (low level section) input to IC300 (E19).
TEL LINE
TEL LINE
PC101 (1,2-4) IC300(E19)
6.4.4.
TAM Interface Circuit
This circuit is to switch between FAX receiving and the external TAM’s message recording automatically.
For details, please refer to TAM Interface Section (P.37).
For details, please refer to TAM Interface Section (P.37).
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