4: Theory of Operation
4-2
TW7201I-MS
4.2
Front panel Assembly
The front panel assembly includes the die-cast front panel and four PC boards
(refer to the Figure 4-2 below) and is connected to the DHSL Modem board
by a ribbon cable through connector J1.
Figure 4-2 Front Panel Assembly Block Diagram
2
4
30
25
24
3, 4
J9
J10
J8
J1
27
SWITCH
Q7/Q8
AUDIO
AMP
LATCH
U1
BACKLITE
DRIVER
KEYPAD
BOARD
SWITCH
MATRIX
SWITCH BOARD
DISPLAY
DRIVER
DISPLAY
DRIVER
CUSTOM
LCD
LCD
SERIAL
DRIVER
DISPLAY
BOARD
FRONT
PANEL
PROCESSOR
BOARD
DS1
+ 12V
+ 5V
1
2
+ 12V UNREG
J5
J6
J11
J3
J4
TC/TA/SC
ALARM
SQA
TO
DHSL
MODEM
BOARD
INTERNAL
SPEAKER
2
4
VOGAD
U17
MIC.
INPUT
MIC.
INPUT
PRMICA
VOLTAGE
REG.
U15
11
12
CLAR.
8-bit DA
T
A
B
U
S
PROCESSOR
CIRCUITRY
U13
FPTCALM
MIC. AUDIO
J7
1
2
3
4
5
C
C
C
C
R
R
R
R
C
R
C C C
R
R
R
HANDSET AUDIO
HANDSET AUDIO
26
PWR ON
PWR
OFF
2
1
3
RX AUDIO
MULTIPLEX
U11
MULTIPLEX
U12
VOL.
CNTL.
TX
AUDIO
EXT. SPKR
8-BIT DATA BUS
U14
K1B
SPKR
BUTTON
Summary of Contents for TW7201I
Page 2: ......
Page 4: ......
Page 10: ......
Page 16: ......
Page 86: ...TW7201I MS Figure 5 4 DHSL Modem Board Schematic Diagram 994184 Rev E 5 25 ...
Page 99: ...TW7201I MS Figure 5 6 Power Supply Interface Schematic Diagram 994222 Rev D 5 39 ...
Page 104: ...TW7201I MS TW7201I MS Figure 5 8 Switching Board Schematic Diagram 994149 Rev A 5 45 ...
Page 106: ......