* SPICE netlist
R1 N007 N008 560
R2 N008 0 1.2k
Q1 Rx_Com N008 0 0 BC547C
Q3 Tx_Com N003 Tx_Vito 0 BC547C
D1 Rx_HomeCtrl Rx_Com BAT42
D2 Rx_Vito Rx_Com BAT42
R5 N003 3V3 2.7k
Q2 Tx_Com N001 Tx_HomeCtrl 0 BC547C
R4 N001 3V3 2.15k
R6 N002 Tx_Com 270
DVD1 3V3 N002 SFH487
R3 3V3 Rx_Com 4.7k
D4 Rx_HomeCtrl Tx_Com BAT42
V1 3V3 0 3.3
V2 Tx_HomeCtrl 0 PULSE(3.3 0 2 1u 1u 0.1 0.2 5)
V3 Tx_Vito 0 PULSE(3.3 0 0.5 1u 1u 0.1 0.2 5)
QVT1 3V3 N004 N007 0 SFH309
R7 N005 N004 2.7k
V5 N005 N007 PULSE(0 3.3 3.5 1u 1u 0.1 0.2 6)
V4 DTR_HomeCtrl 0 PULSE(0 3.3 1 1u 1u 1 3 2)
Q5 N003 N006 0 0 BC547C
R8 N009 DTR_HomeCtrl 2.7k
Q4 Rx_Vito N009 0 0 BC547C
R9 N006 DTR_HomeCtrl 2.7k
R10 3V3 Rx_HomeCtrl 2.7k
R11 3V3 Rx_Vito 2.7k
.tran 5
+ Cjo=2.97P Vj=.75 M=.333 TT=4.32U type=LED-IR)
+ IKF=10.010E-3 ISE=22.500E-15 NE=1.7206 VAR=300 NK=.2987 RE=59.2
+ CJE=9.212E-12 MJE=0.286 VJE=0.627 FC=0.5 CJC=8.735E-12
+ MJC=0.275 VJC=0.467 TF=0.1E-9)
+ Cjo=13.3p M=0.333 N=1.70 Tt=7.20n )

* LTspice schematic (.asc)
Version 4
SHEET 1 2160 784
WIRE 72 -376 -152 -376
WIRE 184 -376 152 -376
WIRE 184 -360 184 -376
WIRE 136 -296 -152 -296
WIRE 376 -296 376 -328
WIRE 376 -296 232 -296
WIRE 440 -296 376 -296
WIRE 808 -296 520 -296
WIRE 808 -232 808 -296
WIRE 264 -200 -152 -200
WIRE 264 -136 264 -200
WIRE 280 -136 264 -136
WIRE 376 -136 376 -296
WIRE 376 -136 344 -136
WIRE -120 -120 -152 -120
WIRE 72 -120 56 -120
WIRE 184 -120 152 -120
WIRE 424 -120 424 -168
WIRE 808 -120 808 -168
WIRE 808 -120 424 -120
WIRE 424 -104 424 -120
WIRE 808 -88 808 -120
WIRE 184 -72 184 -120
WIRE 184 -72 56 -72
WIRE 936 -40 872 -40
WIRE 1080 -40 1016 -40
WIRE -120 -24 -120 -120
WIRE -104 -24 -120 -24
WIRE -8 -24 -24 -24
WIRE 1080 -24 1080 -40
WIRE 184 8 184 -72
WIRE 264 8 264 -136
WIRE 280 8 264 8
WIRE 424 8 424 -24
WIRE 424 8 344 8
WIRE 56 40 56 24
WIRE 136 72 -152 72
WIRE 376 72 376 -136
WIRE 376 72 232 72
WIRE 808 72 808 8
WIRE 808 72 552 72
WIRE 1080 72 1080 56
WIRE 1080 72 808 72
WIRE 424 88 424 8
WIRE -952 104 -1064 104
WIRE -792 104 -792 56
WIRE -792 104 -952 104
WIRE -1064 152 -1064 104
WIRE -952 152 -952 104
WIRE 552 152 552 72
WIRE 56 168 -152 168
WIRE 280 168 56 168
WIRE 424 168 424 88
WIRE 424 168 344 168
WIRE -456 200 -456 56
WIRE 424 200 424 168
WIRE -568 232 -568 56
WIRE 56 232 56 168
WIRE 552 248 552 232
WIRE 552 248 488 248
WIRE -792 264 -792 104
WIRE -680 264 -680 56
WIRE 552 264 552 248
WIRE -1064 280 -1064 232
WIRE -952 280 -952 232
WIRE -120 280 -120 -24
WIRE -104 280 -120 280
WIRE -8 280 -24 280
WIRE 56 360 56 328
WIRE -792 392 -792 344
WIRE -680 392 -680 344
WIRE -568 392 -568 312
WIRE -456 392 -456 280
WIRE 424 392 424 296
WIRE 552 392 552 344
FLAG 552 392 0
FLAG 424 392 0
FLAG -152 168 Rx_Vito
FLAG -152 -200 Rx_HomeCtrl
FLAG -152 -296 Tx_HomeCtrl
FLAG -152 72 Tx_Vito
FLAG -152 -376 3V3
FLAG -680 392 0
FLAG -568 392 0
FLAG -792 392 0
FLAG -792 56 3V3
FLAG -568 56 Tx_Vito
FLAG -680 56 Tx_HomeCtrl
FLAG 424 -168 3V3
FLAG 376 -328 Tx_Com
FLAG 424 88 Rx_Com
FLAG -152 -120 DTR_HomeCtrl
FLAG -456 392 0
FLAG -456 56 DTR_HomeCtrl
FLAG 56 40 0
FLAG 56 -120 3V3
FLAG 56 360 0
FLAG -1064 280 Rx_HomeCtrl
FLAG -952 280 Rx_Vito
SYMBOL res 536 136 R0
SYMATTR InstName R1
SYMATTR Value 560
SYMBOL res 536 248 R0
SYMATTR InstName R2
SYMATTR Value 1.2k
SYMBOL npn 488 200 M0
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL npn 232 8 R90
SYMATTR InstName Q3
SYMATTR Value BC547C
SYMBOL schottky 280 24 R270
SYMATTR InstName D1
SYMATTR Value BAT42
SYMBOL schottky 280 184 R270
SYMATTR InstName D2
SYMATTR Value BAT42
SYMBOL res 168 -136 R90
SYMATTR InstName R5
SYMATTR Value 2.7k
SYMBOL npn 232 -360 R90
SYMATTR InstName Q2
SYMATTR Value BC547C
SYMBOL res 168 -392 R90
SYMATTR InstName R4
SYMATTR Value 2.15k
SYMBOL res 536 -312 R90
SYMATTR InstName R6
SYMATTR Value 270
SYMBOL LED 824 -168 R180
SYMATTR InstName VD1
SYMATTR Value SFH487
SYMBOL res 408 -120 R0
SYMATTR InstName R3
SYMATTR Value 4.7k
SYMBOL schottky 280 -120 R270
SYMATTR InstName D4
SYMATTR Value BAT42
SYMBOL voltage -792 248 R0
SYMATTR InstName V1
SYMATTR Value 3.3
SYMBOL voltage -680 248 R0
SYMATTR InstName V2
SYMATTR Value PULSE(3.3 0 2 1u 1u 0.1 0.2 5)
SYMBOL voltage -568 216 R0
SYMATTR InstName V3
SYMATTR Value PULSE(3.3 0 0.5 1u 1u 0.1 0.2 5)
SYMBOL npn 872 -88 M0
SYMATTR InstName VT1
SYMATTR Value SFH309
SYMBOL res 1032 -56 R90
SYMATTR InstName R7
SYMATTR Value 2.7k
SYMBOL voltage 1080 -40 R0
SYMATTR InstName V5
SYMATTR Value PULSE(0 3.3 3.5 1u 1u 0.1 0.2 6)
SYMBOL voltage -456 184 R0
SYMATTR InstName V4
SYMATTR Value PULSE(0 3.3 1 1u 1u 1 3 2)
SYMBOL npn -8 -72 R0
SYMATTR InstName Q5
SYMATTR Value BC547C
SYMBOL res -8 264 R90
SYMATTR InstName R8
SYMATTR Value 2.7k
SYMBOL npn -8 232 R0
SYMATTR InstName Q4
SYMATTR Value BC547C
SYMBOL res -8 -40 R90
SYMATTR InstName R9
SYMATTR Value 2.7k
SYMBOL res -1080 136 R0
SYMATTR InstName R10
SYMATTR Value 2.7k
SYMBOL res -968 136 R0
SYMATTR InstName R11
SYMATTR Value 2.7k