Modem status lights - Siemens 5100B, 4100, and 4100B

Learn what your modem status lights mean and how to use them to troubleshoot problems with your modem or gateway.


Learn about your modem status lights

The following chart explains each status light and what it means.

Status LightStateDescription
PowerOffPower is off or modem is not getting power.
Solid GreenPower is on.
Flashing GreenCheck modem setup.
EthernetOffNo Ethernet connectivity or modem is off.
Solid GreenA device is connected by Ethernet to the modem.
Flashing GreenProblem with network card or cable.
DSLOffDSL signal not detected or modem is off.
Solid GreenModem is connected to DSL.
Flashing GreenCheck modem setup (make sure your DSL line filters are properly set up).
InternetOffModem is not connected to the Internet or modem is off.
Flashing GreenModem is attempting to connect to the Internet.
Solid GreenModem is connected to the Internet.
ActivityOffNo network activity (this is OK).
Flashing GreenNormal DSL traffic flow.
Solid GreenNormal DSL traffic flow.
Last updated: January 21, 2025

Was this guide helpful?