callPreferenceURI 'Labeled URI format to point to forwarded address and type of forwarding 0.0.8.350.1.1.8.1.1 caseExactMatch caseExactSubstringsMatch 1.3.6.1.4.1.1466.115.121.1.15 callPreferenceURIObject callPreference object 0.0.8.350.1.1.8.2.1