Cisco DPC3208 User Manual page 30

Chapter 1 Introducing the DOCSIS Cable Modem
power (without AC power). Most LEDs are disabled if the unit is operating on
battery power. In this mode, the POWER LED blinks to indicate that the unit is
operating under battery power.
The cable modem should only run on battery power when AC power has failed.

If the POWER LED indicates that the unit is running on battery power, but the
AC power has not failed, verify that the power cord is plugged into a working
AC outlet.
6 4027620 Rev A