Each trunk channel in the system is assigned an appearance ID, starting from 01 upwards. You cannot edit or change the IDs but they are displayed in the trunk settings.
Default Line Buttons
For systems running in Key mode, all extension users are assigned a number of line appearance buttons by default. Usually one for every analog trunk. This is controlled by the system's Number of Lines setting.
Programming a Line Button
1.Click on User in the menu bar.
2.Highlight the required user by clicking on them.
3.Click on the 
edit icon in the Button Programming panel on the right.
4.The current button programming for the user is displayed.
5.In the Program Buttons panel click on the button that you want to program. The current settings of that button are displayed in the Button Specification panel.
6.Click on the Assign Feature button.
7.Select Line Assignment.
8.Select the line appearance ID that you want the button to match.
9.Select the ringing option.
•Immediate
Provide audible alerting as normal.
•Delayed Ring
Only provide audible alerting after approximately 15 seconds.
•No Ring
Do not provide any audible alerting.
10.Click OK.