Yealink SIP-T48G Administrator's Manual page 157

Parameters
Configures the desired line to apply the block out rule. The digit 0 stands for all lines.
If it is left blank, the block out rule will apply to all lines on the IP phone
Permitted Values:
0 to 16 (for SIP-T48G/T46G/T29G)
0 to 12 (for SIP-T42G)
0 to 6 (for SIP-T41P/T27P)
0 to 3 (for SIP-T23P/G)
0 to 2 (for SIP-T21(P) E2)
Example:
dialplan.block_out.line_id.1 = 1,2,3
Note: Multiple line IDs are separated by commas.
Web User Interface:
Settings->Dial Plan->Block Out->Account
Phone User Interface:
None
To create a block out rule via web user interface:
1. Click on Settings->Dial Plan->Block Out.
2. Enter the desired value in the BlockOut NumberX field.
3. Enter the desired line ID in the Account field or leave it blank.
If you leave this field blank or enter 0, the block out rule will apply to all accounts on
the IP phone.
4. Click Confirm to add the block out rule.
Configuring Basic Features
Permitted Values Default
.
143