Yealink W53H Cordless: Factory reset

Resetting the Handset:

You can reset individual settings that you have configured on the handset. Resetting handset will not overwrite the settings of the directory, call history, voice mail and the handset registration. But other customized settings on the handset will be reset to factory after handset reset. 

Procedure:
1. Navigate to OK button -> Settings-> System Settings-> Handset Reset.
The phone prompts whether to reset the handset.

If it asks for a PIN enter: 0000

2. Press Yes.