Aastra Telecom 6755i - Manual (Page 143)

Model 6755i IP Phone User Guide 135
Line Keys, Programmable Keys, and Softkeys
Expansion Module Keys
8. Select from “Key 1” through “Key 36” (M670i)
or
Select from “Key 1” through “Key 60” (M675i)
9. In the "Type" field, select Services.
10. (M675i) In the "Label" field, enter a label to apply to this key.
11. Click to save your changes.