Voice Engineer

The Voice Engineer owns day-to-day engineering support of the voice and unified communications environment for the Mosaic Infrastructure Managed Services engagement, spanning roughly 60 sites across the United States, Canada, Brazil, Peru, and Paraguay. The current environment includes a legacy Cisco Unified Communications Manager (CUCM) estate that is being progressively decommissioned as the client transitions to modern cloud-based calling. This role supports and stabilizes the existing voice platform, executes moves/adds/changes/deletes (MACDs), troubleshoots voice quality and connectivity issues, and plays a hands-on role in migration and decommission activities in coordination with the network team.

• → Provide day-to-day operational support for the Cisco CUCM environment, including call routing, dial plans, device registration, voicemail, and related UC services.
• → Execute voice MACDs (moves, adds, changes, deletes) for users, devices, hunt groups, and call flows through the account's request and change processes.
• → Troubleshoot voice quality, registration, and connectivity issues across sites, including SIP trunking, gateways, and QoS-related problems, escalating to carriers or the network team as needed.
• → Support the phased decommission of the legacy CUCM estate, including site-by-site discovery, migration planning inputs, cutover execution, and post-cutover validation.
• → Coordinate with carriers and telecom vendors on circuit, trunk, and number porting activities in support of migrations and incident resolution.
• → Maintain accurate documentation of the voice environment, including dial plans, trunk inventories, gateway configurations, and site voice profiles.
• → Partner with the Network Engineer Lead and network team on voice-impacting network changes (QoS, VLANs, firewall rules for voice traffic).
• → Support Microsoft Teams calling/telephony integration activities where in scope of the client's target-state voice platform.
• → Participate in scheduled after-hours change windows for voice changes and migration cutovers.
• → Track and report status of voice-related tickets, projects, and decommission milestones to the Network Engineer Lead.

• Bachelor's degree in Information Technology, Telecommunications, or a related field, or equivalent professional experience.
• 3+ years of hands-on voice/UC engineering experience, including administration of Cisco Unified Communications Manager (CUCM).
• Working knowledge of voice protocols and technologies: SIP, RTP, QoS, voice gateways, and SIP trunking.
• Experience executing voice MACDs and troubleshooting voice quality issues in a multi-site environment.
• Experience working with telecom carriers on trunks, circuits, and number porting.
• Familiarity with ITIL incident and change management processes.
• Strong verbal and written communication skills in English B2+

• Experience supporting voice platform migrations or decommissions (CUCM to cloud calling, Teams Phone, or similar).
• Cisco Collaboration certification (CCNA/CCNP Collaboration) or equivalent.
• Experience with Microsoft Teams Phone / Direct Routing.
• Experience in a managed services environment supporting enterprise clients.
• Trilingual Spanish/English/Portuguese is a MUST, given the engagement's multi-country footprint.

• Cisco Unified Communications Manager (CUCM), Unity Connection, and related UC tooling.
• SIP trunking, voice gateways (ISR/CUBE), and dial plan administration.
• Voice troubleshooting tools (packet capture, RTMT, or similar).
• Microsoft Teams Phone / Direct Routing is a plus.
• ITSM/ticketing platforms (ServiceNow or equivalent).

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