What security features are offered with SIP trunks?

This depends on the SIP provider. Broadvox can implement SIP trunks over a dedicated or VPN-enabled connection. Actually, it’s much harder for somebody to intercept a VOIP call than a traditional PRI or analog call. To intercept a traditional Public Switched Telephone Network (PSTN) call, the hacker only needs limited telco knowledge and access to the building junction box. To hack a VOIP call, the hacker must have significant networking knowledge as well as hack one or more networks that have been deployed with ample security precautions.