1. Unplug your machine from the electrical outlet and then plug it back in.
2. Open the top cover by lifting the lever on the right side of the cover and then close securely. 
3. Press the keys and see if they respond.
   (Hook key should give a dial tone, Menu/Set should display options on LCD, etc)
4. If the keys are still triple beeping or not responding examine the control panel to see if any of the keys are stuck.
   If one key is stuck, none of the other keys will respond properly. You can do this by pressing the keys and seeing if they move.
   If you find a key that is stuck down, try wiggling it to see if it can be freed.
   If you are able to free the key, trying pressing the keys again and see if they respond.
   (Hook key should give a dial tone, Menu/Set key should display options on LCD, etc).

If none of the keys appear to be stuck or freeing a stuck key did not resolve the problem, please contact the Brother office in your country.