UX-108DE
5 – 8
[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 9 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. Cl detection circuit
9. 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.
H
L
CML
CI DETECTOR
0
1
SPEAKER
TEL
LINE
+5V
+24VA
DG
RX MUTE
CI
RX MUTE
SP MUTE
CI
BZCONT
TXCONT
BZCONT
VOL C
VOL B
VOL A
TELOUT
TEL IN
EXT.
HANDSET
RXIN
TXOUT
CML
TXCONT
SIGTX
SIGRX
0
1
0
1
GAIN-C
CML
XFC3
MODEM
(R96DFXL-CID)
CONTROL PWB
TEL/LIU PWB
DP GEN.
DP ON
RHS
RHS
DP ON
Summary of Contents for UX-108
Page 27: ...UX 108DE 2 18 M E M O ...
Page 40: ...UX 108DE 3 13 M E M O ...
Page 61: ...6 7 UX 108DE Control PWB parts layout Top side ...
Page 62: ...6 8 UX 108DE Control PWB parts layout Bottom side ...
Page 65: ...6 11 UX 108DE TEL LIU PWB parts layout Top side ...
Page 66: ...6 12 UX 108DE TEL LIU PWB parts layout Bottom side ...