Addi-Data ADDICOM APCI-7300, Technical Description

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Connecting the peripheral APCI-7xxx
RS485 cabling
Fig. 7-7: RS485 cabling - 4-port serial interface
Current loop (20 mA) cabling
Active / passive :
When a transmitter and a receiver communicate, one of
them has to supply the necessary current. If the transmitter supplies the
current, it is active. The receiver is passive. In reverse, if the receiver
supplies the current, it is active.
Fig. 7-8: Active transmission/active reception
4-port serial interface
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