.. _class_of_service: Class of Service ---------------- Customer administrators and higher level administrators can create and maintain a Class of Service (CoS) that apply to subscribers. A CoS specifies the |Unified CM| and Calling Search Spaces (CSS) for a subscriber's line, thereby indicating whether local, national and international numbers can be called. An administrator can create a CoS at a customer level hierarchy. A |unified CM| is specified. A drop-down list of those available at the customer level is shown. Optional device and line CSSs can also be added - either selected from those existing on the |Unified CM|, or else added. Macros can also be used when adding new CSSs, for example: ``CSS-Gold-{{macro.SITENAME}}``. When a CoS is modified, the |Unified CM| cannot be modified. In order to refer to another |Unified CM|, either clone an existing CoS or else delete it and re-add it. .. |VOSS-4-UC| replace:: VOSS-4-UC .. |Unified CM| replace:: Unified CM