Any call that involves a circuit-switched (TDM) endpoint, such as a DCP or analog telephone, is vulnerable to conventional wire tapping techniques.

Any call that involves an IP endpoint or gateway that does not support encryption can be a potential target for IP monitoring. Common examples are IP trunks to third-party vendor switches.

Any party that is not encrypting an IP conference call exposes parties on the IP call between the unencrypted party and the supporting media processor to monitoring. This vulnerability can occur although the other IP links are encrypting.