Panasonic KX-MB771GR Service Manual page 26

KX-MB771GR
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 Soc IC300.
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; Remote fax activation circuit.
Refer to NCU SECTION (P.27) for the details.
6.3.4.2. BLOCK DIAGRAM
IC100
RING 16
10
9
ARXD
5
ATXD
6
IC200
BTXD 4
10
BRXD 5
16
1
IC101
3
5
13
6
16
14
12
1
8
15
9
EXTRLY
AGC
26
HS_MIC(+)
HS_MIC(+)
HS_SP(+)
HS_SP(-)
SP(+)
SP(-)
KX-MB771GR: MAIN BOARD BLOCK DIAGRAM
T
R
T
R