By default when the first extension is added to the phone it automatically assigns two Flexible Buttons as line keys.
When you add the second extension by it will register the extension but wont except calls and there is no way to place calls from the new extension.
Here are the steps required to get the seconds extension working.
This going to assume that the first and second line settings are already configured on the phone.
1) Press the “Phone” button
2) Press the “Flexible Button” key (It looks like a circle with an arrow pointing left)
3) Press the “Menu” button and then “Start Flexible Button Prog Mode”
4) Press an empty box and select “Phone Function”
5) Set the following: Type: DN, Parameter: Ringtone 1 [New Extension Number], Label name: [Label of Extension]
6) Press “OK”. Repeat steps 4 and 5 to add additional line buttons to the same extension or add new extensions
7) When you are done press “Back”
Now you can receive and place calls by using the buttons that were created by the steps above.
VoIP4EA 