Siemens Electrical Lean Switch - Manual (Page 26)

Ports and Displays
Industrial Ethernet
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4.1.3 Displays
Power display (green LED)
The status of the power supply is signaled by a green LED:
Status Meaning
lit green Power supply L+ is connected
Not lit Power supply L+ is not connected or <14 V
Port status display (green/yellow LEDs)
The status of the ports is signaled by four LEDs:
Status Meaning
Port 1 to 4 LED lit green TP link exists, no data reception
Port 1 to 4 LED lit yellow TP link exists, receiving data at TP port