Mục được đánh dấu với thẻ "GXP2200EXT":

The GXP2200EXT is the extension module that can be added to the GXP2140, GXP2170, and GXV3240 Enterprise IP phones. The module includes 20 extension keys and 2 arrow keys for page switching (allowing for 40 lines to be displayed), with a large LCD screen for easy viewing. Add up to 4 modules for a total of 160 extensions.