I am unable to hear a dial tone on my handset?

If your DP-710/715 handset is malfunctioning please remove all batteries from the handset for a period of 10 seconds the re-insert the batteries into the handset as you found them. You can find a video and images below. If you are still unable to make or receive calls using your DP-710/715 then disconnect power from the base unit for a period of 10 seconds before reconnecting power. It may take as long as 15 minutes for your base unit to provision.

Follow the images below in reverse to re-insert the batteries into the handset unit.