Yealink SIP-T21 - Manual (Page 69)

Customizing Your Phone
59
For more information on the valid values of Account field, refer to Replace Rule on
page 55 .
4. Click Confirm to accept the change.
Note
You can block some specific numbers from being dialed on your phone. When you dial
a block out number on your phone, the dialing will fail and the LCD screen will prompt
“Forbidden Number”. You can add 10 block out rules at most on your phone.
To add a block out number via web user interface:
1. Click on Settings->Dial Plan->Block Out.
2. Enter the desired value in the BlockOut Number field.
3. Enter the desired line ID in the Account field or leave it blank.
Area code is configurable via web user interface only.