How To Intercom Using Hosted Cisco SPA5xx SIP Phones
http://www.youtube.com/watch?v=wPnsuv25SQY&list=PLNCEjKAwLkM-PdaV1rd_WzXK7DKBgGxig
In this tutorial, we demonstrate how to perform a one-touch intercom for your Cisco IP SPA 303, 504, or 508 Series business telephone system.