The Base Station is designed to notify you using a few different colors and sounds.
Bouncing Green: Looking for readings from your baby.
Pulsing Green: Receiving readings.

Flashing Blue: Sock out of range from Base Station, depleted battery or signal blocked.
Flashing Yellow: Sock has fallen off or is improperly placed.

Flashing Red: Heart rate or oxygen level are outside specified limits.
Blinking Orange: The Sock was placed on a Base Station it is not paired to.
White: Sock is plugged in and charging.
Bouncing White: Sock is not paired to Base Station.