Circuit Description Of Tel/Liu Pwb - Sharp UX-510A Service Manual

[3] Circuit description of TEL/LIU PWB

(1) TEL/LIU block operational description
1) Block diagram
L1
CML
M
C
L2
B
HANDSET
RX
TX
BIT7 BIT6 BIT5 BIT4
DAC
MIC GAIN L/O E SPKR E
IACR1
GAIN
TXRX
IACR2
LOOP ATTENUATION
IACR3
2) Circuit description
The TEL/LIU PWB is composed of the following 7 blocks.
1. Speech circuit section
2. Dial transmission section
3. Speaker amplifier section
4. Ringer circuit section
5. Externally connected TEL OFF HOOK detection circuit
6. CI detection circuit
7. Signal/DTMF transmission level & receiving level
TEL/LIU PWB
TXOUT
CI
RXIN
TELIN
TELMUTE
DTMFMUTE
TELOUT
BIT3 BIT2 BIT1 BIT0
ADC
L/I E MIC E
GAIN
LINEOUT
MICBIAS
RXTXLOOP
SEL
LINE SEL
CONTROL PWB SP OUT
ENABLE
SPKRP-P
MICP
0,20,25,30dB
LINEIN
LINEOUT
LINEOUT
ENABLE
SPEAKER
SPMUTE
Fig. 6
3) Block description
1. Speech circuit section
•
The receiver volume is an electronic volume type, this model is
switched in 2 steps.
2. Dial transmission section
•
D.P. transmission: The CML relay is turned on and off for control in
•
DTM transmission: It is formed in the modem, and is output.
3. Speaker amplifier section
•
Ringer volume
•
Speaker volume :It is controlled by the attenuator value of the
4. Ringer circuit section
•
The ringer sound is formed in the tone of modem when CI signal is
detected. The amplifier circuit drives the speaker of the main body.
5 – 8
INTEGRATED ANALOG
20415
RTLOOP
(0:1)
MIC ENABLE
(1:0)
(0:0)
(1:1)
SP
DRIVER
MIC
MIC
GAIN
ENABLE
1
MIC IN
LPF 0
LINE IN
ENABLE
1
LINE IN
LPF 0
LINE
DRIVER LNINSEL
(0:0)
(1:1)
(1:0)
MUTE,0,
–6,–12dB
BZOUT
CML
SPMUTE
DTMFMUTE
RCVOL
VTHON
the DP calling system. (Refer to the attached
sheet.)
:It is controlled by the combination of the
attenuator value of the LINE DRIVER in the
modem and the ringer sending level sent from
the modem.
LINE DRIVER in the modem.
UX-510ATH
FO-1470TH
DAC SIN
DAC GAIN
0,6dB
ADC SOUT
ADC GAIN
0,–4dB
HS
CI
CSWI
PESNS
FRSNS
FAX
ORGSNS
ENGINE
PSNS
SCE114
LEDON
RHS
DRSNS
TXMUTE
TELMUTE
IA-RESET