Wireless wifi microphone for conference room.
You need to install open SIP server and receiver application on PC or Mac.
To use this app you need a free SIP server (like kamailio) without authentication and a SIP client (like Jitsi) configured as a receiver. The name of the client must be "receiver".
Alternatively you can use the command line client "receiver", downloadable from http://www.robertopasini.com/index.php/iphone