3Com SuperStack 3 NBX Administrator's Manual page 159

4 Select the secondary telephone from the scroll list.
5 Click Button Mappings. The Telephone Button Mappings dialog box
(Figure 54) appears.
Figure 54 Telephone Button Mappings Dialog Box
6 For each button that you want to include in the group of bridged
extension buttons:
a Select Bridged Extension from the pull-down list in the Type column.
b Type the extension number of the primary telephone in the Number
column. See Figure 55.
Creating and Managing Bridged Extensions 159