The GXP2200EXT extension module is supported by the GXP2140, GXP2170 and GXV3240. The module includes 20 dual-colored extension keys and 2 arrow keys for page switching (allowing each GXP2200EXT to support up to 40 contacts/extensions.) and features a large backlit LCD screen for easy viewing. Connect up to 4 GXP2200EXT modules to compatible Grandstream phones for a total of 160 contacts/extensions. This expansion module supports traditional call features on each of its programmable buttons, including BLF (busy lamp field, standard or eventlist)Call Park/Pick-up, Speed Dial, Presence, Intercom, and conference/ transfer/forward. The GXP2200EXT is the ideal solution for users that manage high call volumes, including executives and receptionists. By using the GXP2200EXT the telephone attendant can maximize productivity by efficiently monitoring and dispatching multiple incoming calls.