How to use Barix SIP Client with Cisco Unified Call Manager About this document This document explains how to make a Barix Device with SIP-Client-Firmware (Version 2.12 or higher) registering and working with the Cisco Unified Call Manager (CUCM).It was tested with CUCM V8.6.2.BARIX AG | 11.ow to use Barix SIP Client with Cisco Unified Call Manager About this document This document explains how to make a Barix Device with SIP-Client-Firmware (Version 2.12 or higher) registering and working with the Cisco Unified Call Manager (CUCM). It was tested with CUCM V8.6.2. BARIX AG | 11.