Panasonic UF-5500, Service Manual

Page: 35 / 365

35
UF-5500 / 4500
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.36) for the details.
6.3.4.2. Block Diagram
RING
ARXD
ATXD
BTXD
BRXD
IC200
IC100
IC101
EXTRLY
T
R
T
R
SP(+)
SP(-)
)
)
HS_SP(+)
HS_SP(-)
15
5
6
5
6
10
9
8
9
15
1
16
14
12
1
3
13
4
5
10
16
MAIN BOARD BLOCK DIAGRAM