Multitech SocketModem GSM Hardware Manual page 31

Developer Board Schematics
MIC
3
C180
GND
R207
R209
VCC
SPKR
R210 0
R211
3,4
GND
VIN
2,4
C1 .01uF
VCC
14
VCC
DTRTTL
1
3
7
GND
RTSTTL
3
3
CTSTTL
5
3
9
DSRTTL
3
74LCX04
Multi-Tech Systems, Inc. SocketModem GSM Hardware Guide for Developers
C13 .01uF
GND VCC
VCC
U17A
.01uF
47K
47K 3 V+
+
1
2
10K
-
V-
TL082
GND
R212 47K
C183 .001uF
C184 .47uF
25 V
R213 10K
R214 2.7K
C187 4.7pF
U23
4 5
IN-
VO1
3 6
IN+ VDD
VCC
2 7
BYPASS
GND
GND
1 8
GND SHUTDOWN
VO2
LM4861
C190
.1uF
C14 .01uF
GND
16 V VCC
GND
R4 2.7K LED10
U12A
2 R76 47K Q12
2N3904
74LCX04
GND
R17 2.7K
U12B
R78 47K
4 Q13
2N3904
74LCX04
GND
R5 2.7K LED12
U12C
6 R80 47K
Q14
2N3904
74LCX04
GND
R18 2.7K
U12D
R82 47K
8 Q15
2N3904
GND
R205 10K
VCC
C181 1uF
R208 301K
C185
R215 0
C191 .01uF
R216 0
RED LED14 RED R19
LED15 RED R20
LED11 RED
LED16 RED R60
RED
R59
LED13 RED LED17 RED
Chapter 5 – The SocketModem Developer Board
C179 10uF
+
GND
16V
FB25
MLB20
C182 .001uF
.01uF
C186 .001uF
GND
GND
2.7K
U12E
R77 47K 10
Q16
2N3904
74LCX04
GND
2.7K
U13E
R79 47K 10
Q20
2N3904
74LCX04
GND
2.7K
U13D
R81 47K 8
Q18
2N3904
74LCX04
GND
2.7K
U13C
R83 47K 6
Q17
2N3904
74LCX04
GND
31
J18
4
3
5
GND
2
1
5-PIN-STEREO-JACK
100 V
P19 J19
GND
HEADER-2
SHUNT
100 V
J20
4
3
5
2
1
5-PIN-STEREO-JACK
11
DCDTTL 3
11
RITTL 3
9
TXDTTL 3
5
RXDTTL 3