The Teltonika RUT950 4G Router provides several LED status lights including signal strength indicators.  Here is the information relating to the signal strength based upon the LED signal strength lights.

1 LED is light up when signal strength is between -111 and -98 dBm
2 LEDs are light up when signal strength is between -97 and -83 dBm
3 LEDs are light up when signal strength is between -82 and -68 dBm
4 LEDs are light up when signal strength is between -67 and -53 dBm
5 LEDs are light up when signal strength is greather than -52 dBm