Service manual

UX-310DE
FO-730DE/NX-530DE
H
L
H
L
CML
CI DETECT
LINE
EXT.
HI GAIN
TXOUT
TXMUTE
L
H
MODEM
(R96DFXL-CID)
CONTROL PWBTEL/LIU PWB
TEL
TEL
H
L
EARTH
H
L
~
~
+
–
HS AGC
SIDETONE
CANCELER
TXOUT
HS
CI
DPMUTE
DPON
RCVOL2
CML
RCVOL
HS
CI
DPMUTE
DPON
RLYCONT
CML
E-RLY
RXIN RXIN
EXTING
H
L
RCVOL
TEL IN
RX
TX
HANDSET
L
H
TELMUTE
L
H
L
H
DPON
(MPXB)
DPMUTE
(MPXC)
L
H
L
H
L
H
GAINC
CI
HS
TXCONT
RHS
SPMUTE
BZCONT
TEL MUTE
PE9
TEL OUTTEL OUT
TEL IN
VREF
DG
H
L
ON
HOOK
OFF
HOOK
HOOK SW
RHSRHS
TEL MUTETEL MUTE
SPMUTE
L
H
DG
VOL B
VOL A
BZCONT
DPON
CML
FC100M
TXOUT
VOL A
VOL B
TXMUTE
DPMUTE
RCVOL2
RCVOL
RXIN
E-RLY
(RCVOL)
DG
SPEAKER
L
H
BZOUT
TXCONT
GAINC
SIGMUTE
[3] Circuit description of TEL/LIU PWB
(1) TEL/LIU block operational description
1) Block diagram
2) Circuit description
The TEL/LIU PWB is composed of the following 10 blocks.
1. Surge protection circuit
2. Noise filter
3. Dial pulse generation circuit
4. CML relay
5. Matching transformer
6. Hybrid circuit
7. Signal selection
8. Sensor circuit
9. Cl detection circuit
10. Power supply and bias circuit
Fig. 5
3) Block description
1. Surge Protection circuit
This circuit protects the circuit from the surge voltage occurring on the
telephone line.
• The AR1, AR2 protects the circuit from the 425V or higher line
surge voltages.
5 – 8