The light on my NTS/NTL unit is on. What does this mean and how do I address it?

If the light is solid, this indicates a "Fault" or hardware issue. If the light is blinking in a steady fashion, this indicates the unit is in standby mode.

However, if the light is blinking rapidly, this could mean a firmware issue or hardware fault.

A good first step would be to try and flash the Firmware, even if the unit has the current version.