D-Link DWM-222 User Manual page 5

Invalid (U)SIM card
Network signal
Network type
Data service
4. LED Indicator description
State of LED indicator
Red (blinking)
Green solid on
Green blinking
Blue solid on
The (U)SIM is out of service.
Indicate the signal strength of
GSM/GPRS,
EDGE
Description
No SIM card/ Error
Register to network (not connect)
Connected to 4G network
Register to network (not connect)
UMTS,
available,
LTE
HSPA