Because it is line-powered, the phone remains functional during electrical blackouts, making it an excellent emergency backup. VTech CD1113 Corded Trimstyle Phone, Black | staples.ca
Unplug the power adapter, wait 5 minutes, and then reconnect it. Vtech Cd111a User Manual
This is often caused by interference from other electronic devices or a faulty line cord. Try replacing the telephone line cord. Because it is line-powered, the phone remains functional