You can configure the key as a simplified speed dial key. This key function allows you to easily access your most dialed numbers. 

To assign the key as Speed Dial: 

1. Choose Phone-> DSS Key -> Line Key, choose one of the key you want to make the assignment, there is a pull-down menu in the Type field, choose Speed Dial from the list. 
2. In the "Line" field, select a line for which to apply this key, in the “Number” filed enter the extension number you want to perform Speed Dial. 
3. Press Confirm button to save the changes.