The Legacy 6 from Telex is a versatile six-user wireless intercom system ideal for use in field production work or sports applications. It offers full-duplex communication so users can speak and listen simultaneously with no "push-to-talk". Audio is transmitted using 802.11 wireless LAN technology for ease of use and is encrypted using 64-bit DES technology to ensure your conversations stay private.
 
https://www.bhphotovideo.com/c/product/472135-REG/Telex_301950007_Legacy_6_6_User.html