Vtech ERIS Business System Console The UP416 is a console of a 4-line telephone system. It is expandable to a maximum of 15 UP406 desksets, a UP407 cordless handset and a VTech IS6100 cordless headset. Each UP407 Cordless Handset & IS6100 Cordless Headset requires a Console (UP416) or Deskset (UP406) to Operate. You can register only one UP407 cordless handset and one VTech IS6100 cordless headset to a UP416 console or a UP406 deskset. When the console or a deskset has cordless accessories, the accessories are all part of the same extension.Only one device with the same extension can be used at a time. System Set up requires a router.