Omega Engineering iLD Series User Manual page 11

DEVICE #1 DEVICE #29
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iLD Big Display TB4
1 2 3
.........................
DEVICE #31
-Tx/-Rx
-Tx/-Rx
+Tx/+Rx
+Tx/+Rx
GND
Twisted shielded pair
120 Ohm
...............................
Termination resistor
...............................
DEVICE #2 DEVICE #30