Caller ID/Call Waiting. Digital Answering System</br>Extra-Large Tilt Display. Backlit Display. Audio Assist</br>Extra-Loud Ringer</br>DSL Subscribers may need to us a DSL Filter</br>Note - This telephone provides minimal functionality during a power failure. When AC power is not available, the screen is blank and many telephone features do not function. Only touch-tone dialing and handset volume adjustment are supported</br>Extra-large buttons: Enlarged font and extra-large keys make the keypad easy to use. This feature is especially helpful for those who are visually impaired</br></br>Product Description</br></br>Cl4940Wht- Corded Answering System.Troubleshooting steps as follows:1. If you are having trouble hearing on the handset, try replacing the handset cord.  2. Please check if you can hear the dial tone. The volume may be turned down too low to hear the other party.  Press VOLUME ^ on the base to turn up the volume.  3. Try a handset and/or line cord from a working set.   If this corrects the problem, replace the appropriate cord. 4. If you have connected this telephone to a phone jack that has not been used before, or that has not been used in sometime, there may be problems with this jack that you are not aware of.  Use a telephone jack that you know is in proper working order. 5. You may have a line problem.  To test for a line problem, test your unit at another location.  If your unit works at another location, contact your local telephone company.  For any further queries, please reach out to AT&T's technical support @ 1-800-222-3111</br><br/>http://www.amazon.com/gp/product/B007B5VH0E