The Voip Service example is taken from a Java.net featured article, Provisioning Services Through ESB (http://today.java.net/pub/a/today/2005/10/18/service-provisioning-through-esb.html) describes how to orchestrate services through abstraction, providing a VOIP provisioning example developed using Mule.
Homepage POM file JAR file Javadoc'org.mule.examples:mule-example-voipservice:1.3'