An electronic hook switch (EHS) is a device which electronically connects a wireless headset and desk phone. Either Bluetooth headsets or DECT headsets can be used. Users can handle (e.g. answer) calls with the headset only, freeing them from remaining next to the phone. Switching from handset to headset is typically accomplished by pushing a specific button. VT-EHS1 for Cisco 7900, HHC inside of headset. What's in the box 5 x cables