Background information: The commonly used 20mA or current loop interface is still very popular in industrial systems. Due to the low input resistance at the devices, the lines are protected against interfering induced voltage. The port is therefore particularly suitable for use in industrial environments where data is to be transmitted over long distances. The two devices must however be properly isolated from each other. Voltage between devices can result in incorrect data transmission or the destruction of the interfaces.
Technical data:
Number of ports:
2 galvanically isolated 20mA ports
Operating modes:
suitable for active or passive mode
UART:
16550 with FIFO
Base addresses:
03F8H, 02F8H, 03E8H, 02E8H
Interrupts:
IRQ 3..7, IRQ 9..12
Baud rate:
50..57,600 baud
Data format:
any format
Signals:
RxD+, RxD-, TxD+, TxD-
Serial connections:
9-pin SUB-D connector
Galvanic isolation:
Isolation voltage min. 1 KV DC between PC and serial ports
