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Connector P3 - Audio
Pin
Signal
Comments
1
Line out right channel
Audio line level signal
2
Line out left channel
Audio line level signal
3
0 volts
Audio ground
4
Line in left channel
Audio line level signal
5
Line in right channel
Audio line level signal
6
0 volts
Audio ground
7
Speaker negative
Combined left and right audio channels amplified
volts)
8
Speaker positive
Combined left and right audio
Connector – P4 – RS232 & RS232/422/485
Pin
Signal
Comments
1
0 volts
Ground for COM 2 RS232 channel
2
COM 2 RX
RS232 receive channel
3
COM 2 TX
RS232 transmit channel
4
VCC
3 Volts
5
Termination – low
10K ohm to 0
6
Termination – high
10K ohm to 3 volts
7
Termination – signal
120 ohm and 100nF
8
COM 3 Receive –ve
Differential signal
termination to be connected in circuit
9
COM 3 Receive –ve
Differential signal
termination to be connected in circuit
10
COM 3 Rve
Differential signal
then pin 7
11
COM 3 Transmit –ve
RS422/485
COM 3 RS232 Receive
12
COM 3 Trve
RS422/485
COM 3 RS232 Transmit
For those of you who may be puzzled by the termination options
thousand words....
Beta Touch Computer
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Comments
Audio line level signal
Audio line level signal
Audio ground
Audio line level signal
Audio line level signal
Audio ground
Combined left and right audio channels amplified – Negative (not 0
volts)
Combined left and right audio channels amplified - Positive
RS232 & RS232/422/485
Comments
Ground for COM 2 RS232 channel
RS232 receive channel
RS232 transmit channel
3 Volts
10K ohm to 0 volts
10K ohm to 3 volts
120 ohm and 100nF in series and then pin 10 (COM 3 RX +ve)
Differential signal – negative. Connected to pin 9 to allow
termination to be connected in circuit
Differential signal – negative. Connected to pin 8 to allow
termination to be connected in circuit
Differential signal – positive. Connected to 100nF and 120 ohm
then pin 7
RS422/485 Differential signal – negative.
COM 3 RS232 Receive
RS422/485 Differential signal – positive.
COM 3 RS232 Transmit
For those of you who may be puzzled by the termination options; well they say that a picture speaks a
Beta Touch Computer
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Negative (not 0
Positive
in series and then pin 10 (COM 3 RX +ve)
onnected to pin 9 to allow
onnected to pin 8 to allow
positive. Connected to 100nF and 120 ohm
picture speaks a
