This article explains what to do if your phone doesn't ring when there's an incoming call.
INSTRUCTIONS & INFO
If you recently transferred your telephone number to the AT&T Wireless Home Phone, incoming calls will continue to be routed to your previous line until the transfer is complete. To check your transfer status, visit www.att.com/port.
Ensure the WHP Base Unit is connected to a phone and not the in-home phone wiring.
Ensure your home phone is powered on and connected to the WHP Base Unit.
The AT&T Wireless Home Phone may be set to forward calls; dial #21# to exit forwarding mode if enabled.