Example 1: All phones connected to a switchboard in a company start
with 123. A complete phone number in this company is 1234567. The
PBX prefix is 123 and the extension number is 4567.

Example 2: All phones connected to a switchboard in a company start
with 8989. A complete phone number in this company is 8989123. The
PBX prefix is 8989 and the extension number is 123.

Own line settings and phone book entries

If you want to make calls using the phone book in different networks and
use own line settings, you have to store the phone numbers in the phone
book with the phone number elements that differ per network.

For example, you want to make calls using the phone book in networks in
different countries. Then you have to store the phone numbers with
international access code, country code, area code, etc.