Wireless Technology: DECT 1.9 Supports the DECT (digital enhanced cordless telephony) 1.9 standard wireless technology. Wireless DECT standards vary depending on local legislation. Jabra DECT wireless headsets cover the most recognized DECT standards including European standard DECT & US DECT 6.0. If in doubt, check with your Jabra contact if you are using the correct standard. Talk Range (m): Up to 120 m Up to The maximum talk range is 120 meters m Talk Range (feet): Up to 325 ft Talk range defines how far away you can be from the headset base & still be connected & carry on a conversation Unified Communication: Yes The device is fit for Unified Communications Operating System: Windows This device supports Microsoft Windows Connectivity: USB (Universal Serial Bus) This device is connected via USB (Universal Serial Bus) Conference call capacity: 4 Up to 4 headsets can be joined to one base at the same time for conferencing call purposes