Government agency adds Teams calling to M365 GCC High with CallTower

Customer story · Government

CallTower Delivers Voice Enabled Microsoft 365 for GCC High Organizations

An undisclosed U.S. intelligence community agency, referred through Team Consulting Inc, deployed CallTower's voice-enabled Microsoft 365 GCC High to meet OMB M-22-09 zero-trust requirements and gain Teams audio conferencing and PSTN calling.

  • Originally published by CallTower · July 2023
  • Posted here September 13, 2026
  • 3 min read
Published by CallTower
An undisclosed U.S. intelligence community agency case study
$4.5Msole-source ceiling via TCI SBA 8(a)
IL5DoD SRG impact level supported

About An undisclosed U.S. intelligence community agency

The customer is an undisclosed government agency described as a critical component of the United States intelligence community, holding top-level budgetary and advisory roles for intelligence matters related to national security. Its goal is to integrate and coordinate multiple intelligence agencies and sources in defense of the homeland and of U.S. interests abroad. Microsoft referred the agency to Bruce Hargrave's team at Team Consulting Inc (TCI) to help it secure a Microsoft 365 GCC High provider.

An undisclosed U.S. intelligence community agency case study

The challenge

Like other organizations adjusting to work in the covid era, government agencies and contractors needed modern, mobile communication tools without sacrificing security. A recently mandated requirement, OMB M-22-09, calls for a Federal Zero-Trust Architecture (ZTA), which combines strict identity verification with explicit permission for every person or entity accessing network resources, whether inside the network perimeter or remote, and it sets strict data encryption requirements.

The regular version of Microsoft 365 requires security enhancements for agencies and contractors operating under the M-22-09 controls. To get the communication and collaboration capabilities of Microsoft Teams and its integrations, the agency needed Microsoft 365 GCC High, a version of Microsoft 365 designed for these needs, from a vendor with the proper qualifications and security measures to provide it.

Microsoft referred the agency to Team Consulting Inc (TCI) for its know-how in securing a GCC High provider. TCI selected CallTower, a cloud-based, enterprise-class unified communications provider that had been implementing Microsoft 365 GCC High for years.

The solution

TCI and CallTower combined their expertise to work through the security requirements and implementation procedures. Meeting the rigorous controls needed for M-22-09 compliance presents multiple challenges, but as a long-time GCC High provider CallTower was able to anticipate issues, manage expectations and hiccups, and make the right calls to get GCC High running in a timely manner.

CallTower delivered its voice-enabled Microsoft 365 GCC High solution through a white-glove implementation process. The solution pairs CallTower's Direct Routing telephony with the secure GCC High environment, so the agency can use dial-in conferencing and PSTN calling through Microsoft Teams just as it would in the commercial version of Microsoft 365. According to TCI CEO Bruce Hargrave, GCC High complies with the Federal Risk and Authorization Management Program at FedRAMP High and with the security controls of the U.S. Department of Defense Cloud Computing Security Requirements Guide (SRG) for information up to Impact Level 5.

Following the engagement, CallTower and TCI applied for and were awarded a GSA Schedule (also known as the Federal Supply Schedule or Multiple Award Schedule) to streamline Microsoft GCC High acquisition for government customers through pre-negotiated pricing and simplified subcategorization and Special Item Number (SIN) coding. TCI's SBA 8(a) certification also allows federal customers to award sole-source contracts up to $4.5 million, shortening the procurement lifecycle.

The results

  • Agency gained secure, Teams-enabled audio conferencing for regular meetings with internal teams and external partners
  • Dial-in conferencing and PSTN calling now run through Microsoft Teams via CallTower Direct Routing
  • Microsoft 365 GCC High deployment supports OMB M-22-09 zero-trust and data encryption requirements
  • CallTower and TCI subsequently awarded a GSA Schedule, simplifying GCC High procurement for government buyers
  • TCI's SBA 8(a) certification allows sole-source federal contracts up to $4.5 million

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Download the original document as published by CallTower (PDF, 282.6 KB).

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