Aastra 9480i User Manual page 110

Softkeys
2. Select from "Key 1" through "Key 20".
3. In the "Type" field, select Last Call Return.
4. In the "Line" field, select the line you want to apply to this softkey.
Valid values are 1 through 9.
5. Check (enable) or uncheck (disable) the states you want to apply to this softkey.
6. Click Save Settings.
104 Model 9480i IP Phone User Guide