You can access the Personal address book or the Company directory on Cisco 7821 in two ways.
1. Press the Phonebook key on the left side of the handset.
2. Press the soft-key labelled Contacts.
Phonebook
In the phonebook, you can keep any saved numbers you wish. To add a new number to the phonebook simply press the 'Add' button while in the phonebook, fill out the details and press 'Save'.
Company Directory
When you select the Company Directory it will ask you to search for a keyword. Enter the name or part of the name of the person you wish to call and it will show you the results.
You can view more search results on different pages by navigating the soft-keys.