Panasonic TPA60: Factory Reset Handset
A factory reset is a "last resort" in your troubleshooting; it is a master reset to restore the device to its original system state by erasing all of the information stored on the device in an attempt to restore the device's software to its original manufacturer settings.
WARNING: A factory reset will delete all user saved information, such as contacts in Phonebook. Please do NOT factory reset your device unless expressly asked to by a support engineer.
How to Factory Reset a Panasonic TPA60
If you need to factory reset the handset, you can do the following procedure;
- Power off the handset
- Power on the handset
- When the LCD lights White, press and hold the [TALK] button for 10 seconds
- Release the [TALK] button and press [Softkey A] and then dial 
- Press [OK] to enter Maintenance Mode
- Select Reset Handset
- Select [OK]
- Power off -> power on the handset