The baby unit and the parent unit of your Philips Avent baby monitor might be out of operating range. Obstructions, such as walls and trees, can limit the range of your Philips Avent baby monitor. Try a different location or decrease the distance between the baby unit and parent unit. It can take up to 10 seconds before the connection between the units is re-established.
Note: If the signal is lost, the parent unit will beep three times every 20 seconds.