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1I1
GND
TTL RXDOut
TTL TXDIn
+5V
14VDD
8I5
9I6
10O3
11O4
12I7
13I8
2I2
3O1
R11K
LEDPwr
C2100pF
1In
2GND
3Out
T7805CT
C1100pF
R28K
eBUS- (2)
ZNR7V5
1N4148
R3470
R41K
1N4001
10
5
LEDTX
LEDRX
7GND
Pot. RXThreshold
1C
2B
3E
C
A
+
C
A
BC547
+
HEF4011
15
20
A
A
C
C
Rprot100
ZNR3V9
A
A
1N4148
eBUS+ (1)
5I3
6I4
1N4148
A
C
R6100
R5100
R7 prot3000
R8 prot3000
Set this up so that voltage on middle point (green) is3V on high value1.7V on low value