This Recommendation defines the Service Change Reasons that are used in the core H.248.1 protocol. It lists the Service Change Reason code associated with the Service Change Reason code name. It provides a definition of when the Service Change Reason is to be used. It also provides an indication of what text may be included in the Service Change extension to allow further interpretation of the Service Change Reason. Clause 5 provides these details. This revision addresses the following aspects: o Addition of new Error Codes: 472, 473, 511, 543 o Expansion of Error Codes: 401, 500 o Clarification on the usage of Error Text NOTE This Recommendation has been renumbered. It was formerly known as ITU-T Rec. H.248, Annex L.