Solution:

There are three situations about LED status: RS- 1. Always green: That means you power on this module. 2. Extinguish: Data is transmitted from RS-232 to RS-422/485. 3. Momentary red: Data is transmitted from RS-422/485 to RS-232. According to the above information, you can find out LED is blinking with green (green and extinguish) when you search RS-485 network through ADAM-4520/4522, and LED is blinking with orange (green and red) when you get something from RS-485 network.