3.3.4. Phone Settings
A) PhoneBook Function:
Configure *50, you can use PhoneBook, if you need to dial
first number on PhoneBook, press *501#.
B) FXS 48v Standby:
Use when standby.
C) Billing Support:
Enable the call hold, with the HOLD key to use.
3.3.5. Save Changes
When you finish settings, click “save change” save all the settings.