They are used as part of an IP audio infrastructure most times, You will have audio nodes/blades with different inputs. The two big guys are WheatNet or Axia Audio
http://www.telosalliance.com/Axia/#Consoles
http://wheatstone-radio.com/index.php/wheatnet-ip-technology-overview-radio
Recently heard that KNTU upgraded their boards to Wheatstone... https://twitter.com/MarkTLambert/status/629375665293381632