The VTech AM18247 Extension Desk set for the VTech AM18447 Small Business Office Phone System is an expansion desk set only. It requires the VTech AM18447 main console to operate. The AM18247 uses DECT 6.0 technology, which provides strong protection against wiretapping and the best call range while not interfering with wireless routers. Plus, it makes installation a breeze. Simply connect the power cord and push the registration button to pair to the main console. The VTech AM18247 Extension Desk set for the VTech AM18447 Small Business Office Phone System has its own digital answering system with up to 180 shared minutes of incoming messages, outgoing announcements, and memos. It also features individual caller ID/call waiting and 32-number speed dial.