The PBX has a central phonebook which you can create using menu option Services / Directories.
Create a new directory and add your contacts manually, or upload a .csv file.
The contents of the .csv file should be in the following format:
firstname lastname, phonenumber

Example

Create a file called phonebook.csv
Open the file and enter the following details:

Axeos, 0031204160640
John Simmons, 0123456789
Bob Meldo, 02312345267

Upload the file using the 'import contacts from' option shown when you edit a directory you have created.

TIP: When there are may contacts in your directory, the filter function will help you to find specific contacts quickly.

Once the central directory contains the contacts you can edit the phonebook button on your IP Phones and point it to the phonebook on the PBX.

For example, on SNOM phones it is possible to edit the Function Keys Directory value on the SNOM management webinterface of the phone.

Replace the value F_ADR_BOOK with http://ip-pbx/services/snom/phonebook.xml (replace ip-pbx with the IP address of the PBX).

If the IP address of the PBX is 192.168.2.200 the value you enter should be: http://192.168.2.200/services/snom/phonebook.xml

Replace type 'Key Event' with 'Action URL' and click the 'save' button. Now you can test it by clicking on the phone directory button.

NOTE: The Snom M3 and M9 IP DECT phones doe not support this feature as they have their own central phonebook integrated already.