As DoD contractors move more collaboration into Microsoft 365, GCC High Teams Phone is becoming the default choice for organizations that handle Controlled Unclassified Information (CUI). Unlike traditional phone systems, Teams Phone is tightly integrated with email, meetings, file storage, and identity — which means voice can no longer be treated as “out of band” during a CMMC audit.
Auditors increasingly ask one question: “If CUI is discussed over the phone, where does that data live — and who can access it?”. For organizations using GCC High Teams Phone, that question is much easier to answer — if the platform is configured intentionally.
Why GCC High Teams Phone Matters for CMMC
CMMC requires organizations to protect any system that stores, processes, or transmits CUI. Voice communications qualify the moment they are:
- Stored (voicemail, recordings)
- Transcribed
- Logged in a way that references sensitive content
- Integrated with other CUI systems
GCC High Teams Phone is specifically designed to support this reality by providing:
- U.S.-only data residency
- Access restricted to U.S. persons
- Alignment with DoD, DFARS, ITAR, and FedRAMP expectations
- A defensible compliance boundary for CUI
While CMMC does not mandate GCC High, auditors often expect it when Teams Phone is used in environments that handle CUI.
When GCC High Teams Phone is in Scope for CMMC
GCC High Teams Phone becomes in scope when it is authorized to handle CUI, including scenarios where:
- Voicemail messages may contain CUI
- Voicemail transcription is enabled
- Calls are recorded (manual or automatic)
- Call recordings are stored in OneDrive or SharePoint (GCC High)
- Teams meetings with PSTN dial-in discuss and record CUI
- Softphones are used on endpoints inside the CUI enclave
At this point, Teams Phone is no longer just a communications tool — it is a CUI-handling system subject to CMMC Level 2 / NIST SP 800-171 controls.
The Key GCC High Teams Phone Component Auditors Scrutinize
PSTN Voice Calling & Conferencing
- Dial-in meetings discussing CUI
- Meeting recordings and transcripts
- Third-party compliance recording integrations
- Is your carrier partner FedRAMP aligned?
- Does your carrier have an FCL or use cleared US personnel?
- Does that carrier only use US based customer support?
CMMC Controls Commonly Applied to GCC High Teams Phone
When GCC High Teams Phone is in scope, auditors typically map it to:
- AC – Access control (RBAC, least privilege, MFA)
- IA – Identity and authentication (Conditional Access)
- AU – Audit logging and log retention
- SC – Transmission security (TLS, SRTP)
- CM – Configuration management
- MP – Media protection (voice recordings and voicemail)
Organizations should be prepared to demonstrate:
- MFA enforcement for all Teams and admin access
- Secure voice signaling and media encryption
- Logging and monitoring of admin and data access
- User training specific to voice and conferencing
Common GCC High Teams Phone Audit Findings
Even in government cloud tenants, auditors frequently cite:
- Voicemail transcription left enabled by default
- Call recording enabled without authorization
- Teams PSTN meetings used for CUI without policy approval
- No statement in the SSP defining Teams Phone scope
- Incomplete documentation tying Teams Phone to GCC High licensing
These findings are rarely technical failures — they are governance failures.
Best Practices for CMMC Readiness with GCC High Teams Phone
To prepare for a CMMC audit:
- Decide whether GCC High Teams Phone is authorized for CUI
- Document that decision in your SSP and policies
- Disable recording, transcription, and retention unless required
- Enforce MFA and least privilege across Teams and admin roles
- Train users on approved communication methods
- Regularly review Teams Phone policies and audit logs
Intuity UC assists you in making sure your GCC High Teams Phone is authorized for CUI and configured with restricted recording, transcription, access controls, and audit logging.
Final Thoughts
GCC High Teams Phone is one of the most defensible voice platforms for CMMC environments but only when configured intentionally. The advantage of GCC High with Intuity UC PSTN and conferencing solutions offer clearly defined boundaries, U.S.-based operational controls, and defensible auditability.
In CMMC audits, Teams Phone does not create risk on its own. Make sure you are aligned with correct voice implementation team and PSTN partner. Please contact Intuity UC at 800 811-1086 to see how we can assist your organization’s CMMC journey with secure, scalable and highly redundant PSTN calling and conferencing all provided by cleared US based engineers.