One of the best solution is to use a Algo 8180 SIP Audio Alerter. It has Ring and Page functionality. http://www.algosolutions.com/products/Audible-and-Visual-Alerting/8180-sip-audio-alerter.html
You can also use an Algo 8180 SIP Audio Alerter. Very easy to install.http://www.algosolutions.com/products/Audible-and-Visual-Alerting/8180-sip-audio-alerter.html