Technical data

50
W&T
Serial Fiber Optic Interfaces
Applications
A GND level signal on Pin 5 of the TTY connector will place the
20mA interface of the convertor in half-duplex mode whereby
an echo of the sent signals is suppressed.
The interface can be used as an active or passive 20mA
component. In the active mode, the interface supplies the
current required by the respective 20mA loop, while in the
passive mode the loop current must be supplied by the
connected device. The operating mode can be selected for both
loops separately. Examples of interface switching into active/
passive mode are shown in the following drawings:
20mA
RxD +
RxD -
TxD +
TxD -
active/passive
20mA device
Interface Tx loop active, Rx loop passive
1
2
3
4
6
7
8
9
Data Out 20mA
Data Out+
Data Out -
Data Out GND
Data In 20mA
Data In+
Data In -
Data In GND
RxD +
RxD -
TxD +
TxD -
aktive
20mA device
Interface Tx and Rx loop passive
1
2
3
4
6
7
8
9
Data Out 20mA
Data Out+
Data Out -
Data Out GND
Data In 20mA
Data In+
Data In -
Data In GND
20mA
41210
20mA
RxD +
RxD -
TxD +
TxD -
passive
20mA device
Interface Tx and Rx loop active
1
2
3
4
6
7
8
9
Data Out 20mA
Data Out+
Data Out -
Data Out GND
Data In 20mA
Data In+
Data In -
Data In GND
4121041210
Fiber optic
Fiber optic
Fiber optic