Microsoft Teams Voice

Microsoft Teams Phone (Teams Voice) is Microsoft’s cloud calling solution that turns Teams into a full business phone system, enabling PSTN calling, voicemail, call routing, auto attendants, and call queues. It can replace or integrate with existing PBX/telephony using Calling Plans, Operator Connect, or Direct Routing, while keeping calling unified with Teams chat and meetings across desktop and mobile.

Cloud Telephony Platform

Microsoft Teams Voice transforms Teams into a complete cloud PBX system enabling PSTN calling, voicemail, call routing, auto attendants, call queues, and emergency services. It replaces traditional on-premises phone systems with cloud-based telephony that integrates natively with Teams collaboration features, delivering unified communications across devices. 

We act as an extension of their IT team, responsible for day‑to‑day operations, security monitoring, incident response, and continuous optimization. Our focus is on reducing risk, improving reliability, and ensuring the environment evolves as business needs change. Rather than reactive support, we deliver proactive management, governance, and visibility—allowing clients to focus on their business while we ensure the platform remains secure, compliant, and performing as intended.

Flexible PSTN Connectivity Options

Supports three connectivity models: Microsoft Calling Plans (Microsoft as carrier), Direct Routing (bring-your-own SIP trunk via certified SBC), and Operator Connect (managed carrier integration). Organizations select based on licensing cost, carrier relationships, geographic coverage, regulatory requirements, and integration with existing telephony infrastructure.

Enterprise Voice Routing
& Call Control

Advanced call routing engine supporting voice routing policies, dial plans, normalization rules, translation patterns, and number manipulation. Administrators onfigure inbound/outbound call flows, emergency location identification (E911), international dialing restrictions, caller ID policies, call delegation, simultaneous ring, call forwarding, and voicemail transcription.

Session Border Controller
(SBC) Integration

Direct Routing leverages Microsoft-certified SBCs (AudioCodes, Ribbon, Oracle, Cisco) to mediate SIP signaling and media between Teams and SIP trunks or legacy PBX systems.SBCs provide media transcoding, protocol normalization, network security, encryption, survivability, TLS/SRTP termination, and advanced routing logic for complex enterprise telephony environments.

Analog Device &
Legacy Integration

Supports analog endpoints (fax machines, elevators, door phones, PA systems, fire alarms) through Analog Telephony Adapters (ATA) and AudioCodes Media Gateways.Enables coexistence with legacy PBX systems (Cisco CUCM, Avaya, Mitel) via SIP trunking, allowing phased migration strategies while maintaining existing voice infrastructure investments.

Number Management &
Porting

Comprehensive phone number lifecycle management including number porting (LNP) from existing carriers to Microsoft or Direct Routing providers, number assignment and inventory management, phone number policies, caller ID masking, extension dialing, Direct Inward Dial (DID) ranges, and integration with emergency services databases (MSAG, ALI) for regulatory compliance.

How Red X Carbon Does
Teams Voice Differently

Enterprise-Scale Direct
Routing Architecture

Proven expertise designing and implementing 20,000+ seat hybrid enterprise voice migrations combining Operator Connect, Direct Routing, and AudioCodes Media Gateways for analog device integration. We architect highly available SBC clusters, geo-redundant deployments across data centers, and design failover/failback mechanisms ensuring five-nines telephony uptime for mission-critical voice environments.

Advanced Audio Codes
SBC Engineering

Deep technical proficiency deploying AudioCodes Mediant SBCs and Media Gateways for complex telephony scenarios including all aspects of telephony operating models with AudioCodes platforms 1  . Our engineers configure SIP normalization, codec negotiation, DTMF relay, media bypass, TLS certificate chains, SIP OPTIONS ping monitoring, and advanced SBC diagnostics including packet captures and call trace analysis.

Complex Analog
Device Integration

Specialized expertise integrating legacy analog endpoints including overhead PA systems, emergency phones, elevator call boxes, door entry systems, fax machines, and alarm panels using AudioCodes ATA devices and Media Gateways. We design VLAN segmentation for voice traffic, configure FXS/FXO port mappings, implement POTS line replacement strategies, and troubleshoot analog signaling issues ensuring business continuity during cloud voice migrations.

Advanced Normalization &
Routing Logic

Architects complex dial plan normalization rules, translation patterns, and voice routing policies supporting multi-national dialing formats, E.164 number normalization, extension-to-DID mapping, and least-cost routing logic. We design PowerShell-based automation for bulk voice policy assignment, emergency location mapping, and dynamic number manipulation aligned to organizational dial plan requirements and regulatory constraints.

Number Porting &
Carrier Integration

Technical expertise managing large-scale number porting projects coordinating between incumbent carriers, SIP trunk providers, Microsoft Operator Connectpartners, and regulatory bodies (LNP administrators). We develop porting project plans, validate number portability eligibility, coordinate FOC (Firm Order Commitment) dates, configure call forwarding during cutover windows, and execute rollback procedures minimizing telephony disruption during migration.

Multi-Carrier &
Hybrid Telephony Design

Architects hybrid telephony solutions combining Microsoft Calling Plans for simple users, Direct Routing with SIP trunks for complex  contact centers, and Operator Connect for geographic regions lacking Calling Plan coverage. We design inter-tenant call routing for merger/acquisition scenarios, configure survivable branch appliances (SBA)  for WAN failure scenarios, integrate third-party applications (contact  center, call recording, compliance recording), and implement Session Initiation Protocol (SIP) header manipulation for custom business  logic