Top Operator Connect Partners in the USA: An Honest Comparison

Your team has done the research, weighed the options, and landed on Operator Connect. Now comes the part that's actually harder: picking a carrier.

Microsoft's marketplace lists dozens of certified partners, but certified doesn't mean equal. Every provider in that list has met Microsoft's technical bar. That tells you they can connect to Teams, but it tells you nothing about what happens when a number port goes sideways at 6 PM on a Friday, or whether you'll get a live engineer or a ticket queue. Nor does it tell you what your real per-user cost looks like once the surcharges land.

This guide breaks down the top Operator Connect partners serving the U.S. market, across the factors that actually matter before you commit. We'll cover pricing transparency, support models, compliance capabilities, and who each provider is genuinely built for.

How to Evaluate an Operator Connect Partner

Before comparing Operator Connect providers, let’s clarify what separates them. These are the five areas where we see the biggest gaps between carriers.

1. Coverage. Does the carrier serve your cities, your buildings, and your remote workforce? National coverage claims are common, but the reality varies. Some providers own infrastructure in key markets while others resell access. That distinction matters for call quality and troubleshooting.
   
   
2. Pricing transparency. This is where many IT directors get burned. Some carriers publish clean per-user rates. Others bundle PSTN and usage charges into a single line item, making it nearly impossible to understand what you're actually paying for or to forecast costs as you scale. Find a carrier that will separate the cost for users and the cost for telephone service. Some carriers will combine these into a single cost per user, and you'll end up overpaying for phone lines and service you don't need and won't use.
   
   
3. Support model. There's a wide range here. Some partners offer 24/7 access to live US-based engineers. Others route you through a ticket queue or a tiered system where response times depend on your account size. Ask specifically what support looks like at your spend level, not just what's on the website.
   
   
4. Compliance fit. If you're in government contracting, defense, healthcare, or finance, this one can be a dealbreaker. SOC II, HIPAA, FedRAMP, and GCC High readiness vary significantly across providers, and not every carrier that claims compliance can back it up in practice.
   
   
5. Feature depth. Operator Connect handles core PSTN calling, but your requirements probably don't stop there. Call recording, SMS, international coverage, CRM integrations, and the ability to run Direct Routing alongside OC are all differentiators worth weighing based on your specific needs.

The Top Operator Connect Providers

Here’s a breakdown of the major certified Operator Connect partners serving the US market. We’ve organized them by what they're actually built for, as every carrier here has its own strengths. The question is whether those strengths are the best fit for your situation.

Microsoft Calling Plans

Microsoft Calling Plans isn't technically an Operator Connect partner. It's Microsoft's own native PSTN offering, built directly into Teams. But it comes up in nearly every Operator Connect evaluation, so it's worth addressing head-on.

Best for: Small organizations (under 300 users) with straightforward calling needs and no existing carrier relationship.

Strengths: Deepest Teams integration of any option on this list. The setup is simple, billing runs through your existing Microsoft agreement, and there's no third-party carrier to manage. If your calling footprint stays within Tier 1 markets, it's the path of least resistance.

Potential drawbacks: The 300-user cap is a hard ceiling. Coverage outside major metros gets thin, and the bundled pricing model that feels convenient at 50 seats can become costly at 200. There's also no flexibility to mix in Direct Routing or customize your voice setup; you're locked into Microsoft's way of doing it.

If you're reading a guide like this, there's a decent chance you've already outgrown it or are about to.

Atlantech Online

Atlantech owns its own fiber network in the DC/MD/VA corridor and offers both Operator Connect and GCC High Direct Routing from a single provider.

Best for: SMBs and government contractors nationwide that need Operator Connect, GCC High Direct Routing, or both.

Strengths: Atlantech publishes per-user pricing without bundled surcharges, so what you're quoted is what you pay. Our fiber infrastructure is in the Mid-Atlantic, and our voice and Teams Calling services are available across the US. Your first month is free, with no setup or porting fees.

On the support side, you get a live US-based engineer 24/7, typically in under 10 minutes. For organizations operating in the GCC High space, Atlantech is one of the few carriers that can deliver both commercial Operator Connect and compliant Direct Routing for GCC High under one roof.

Ashley Moreau at SilverEdge described setup as taking "literally 5 minutes." Patrick Binsol at Lerch Early called it the "smoothest Teams Calling cutover" they'd experienced.

Potential drawbacks: Atlantech’s focus is on SMBs and government contractors; that's where our support model, compliance capabilities, and pricing are built to deliver the most value. If you're a large commercial enterprise needing a carrier that can bundle Operator Connect with a broader portfolio of global WAN, mobile, and managed network services, you'll likely get a better fit from one of the national carriers covered below.

Lumen (CenturyLink)

Lumen is one of the largest fiber network operators in the US, and for enterprises with a distributed national footprint, that infrastructure backbone is a genuine differentiator.

Best for: Large enterprises with offices across the US that need a single carrier with deep national reach.

Strengths: Lumen's fiber network is extensive, and their SLA commitments reflect that scale. For organizations that need reliable voice alongside a broader portfolio of enterprise connectivity services (WAN, SD-WAN and security) Lumen can consolidate a lot under one roof. Published pricing sits at $14/user/month.

Potential drawbacks: The $14/user rate comes with a 36-month commitment, and early termination fees apply. Support quality can also vary depending on your account tier. Larger accounts tend to get more responsive service, while smaller ones may find themselves lower in the queue. If you're an SMB or mid-market organization, the enterprise-first model may not work in your favor.

Verizon

If your organization is already integrated in the Verizon ecosystem through things like mobile plans, WAN, and SD-WAN), adding Operator Connect through them has an obvious logic to it. Verizon was also the first provider to offer Direct Routing, Operator Connect, and Teams Phone Mobile under one umbrella.

Best for: Large enterprises already invested in Verizon's wireless and networking portfolio.

Strengths: Nationwide coverage backed by one of the largest network infrastructures in the country. Verizon offers a 100% network availability SLA, and their Teams Phone Mobile option unifies your desk and mobile number on a single device. For Fortune 500 organizations that want a single point of accountability across voice, wireless, and data, Verizon can deliver that.

Potential drawbacks: Pricing is not publicly available, and you should expect premium rates. The support experience tends to follow a Big Telecom model, where your account size determines how responsive things get. If you're a mid-market company without a dedicated account team, the experience can feel very different from what Verizon puts in its case studies.

AT&T

AT&T has been a fixture in enterprise voice for decades, and its Operator Connect offering leans into that history.

Best for: Organizations with existing AT&T voice and wireless contracts looking to consolidate into Teams.

Strengths: Broad national reach and a deep history in enterprise voice. AT&T's Teams Phone Mobile offering unifies your Teams number and mobile number on a single device, and they've been building out Copilot integration for Teams calling workflows. If you're already paying AT&T for wireless, bundling Operator Connect into that relationship can simplify procurement.

Potential drawbacks: Pricing is not transparent, and Teams Phone Mobile requires an AT&T wireless subscription, which means you're committing to their mobile ecosystem as a prerequisite. Like most large carriers, there's a layer of complexity in dealing with AT&T that smaller or mid-market organizations often find frustrating. If you don't already have an existing AT&T relationship, there's not a compelling reason to start one here.

Pure IP

Pure IP is a voice specialist, not a generalist. Where most providers on this list lead with US coverage and treat international as an add-on, Pure IP builds from the other direction.

Best for: Multinational organizations that need consistent Teams calling across countries.

Strengths: A coverage that spans 137 countries. This puts them well ahead of most US-focused carriers on international reach. They price Operator Connect and Direct Routing the same, so you're not penalized for choosing one delivery method over the other. And because voice is their entire focus, you're not competing for attention with a carrier's broader product portfolio.

Potential drawbacks: Pure IP has less brand recognition in the US SMB market, so if your needs are primarily domestic, it may not be the most natural fit. Their strength is breadth of coverage across borders, not depth of presence in any single US market.

CallTower

CallTower has been in the Operator Connect program since launch day and brings a UCaaS-forward approach to Teams calling. It places a strong emphasis on integrations and managed services over most pure-play carriers.

Best for: Mid-market organizations with CRM integration needs and GCC High requirements.

Strengths: CallTower was one of the earliest certified Operator Connect partners, and they've offered GCC High Direct Routing since 2019. They support SMS/MMS alongside voice, and their Salesforce integration is a standout if your workflows depend on CRM connectivity. For mid-market teams that want a more managed experience rather than just a dial tone, CallTower is worth a look.

Potential drawbacks: Pricing isn't public, and per-component cost breakdowns are hard to come by. If pricing transparency is high on your list, you'll need to push for specifics during the sales process.

Bandwidth

Bandwidth is a different kind of Operator Connect partner. They're a carrier-grade network operator, but their offering is built for organizations that want programmatic control over their voice infrastructure rather than a traditional managed service.

Best for: Developers, MSPs, and tech-forward enterprises that want API-level control over voice.

Strengths: Bandwidth owns network infrastructure in 34 US markets and layers a strong API platform on top of it. If your team wants to build custom call routing, automate number provisioning, or integrate voice into your own applications, Bandwidth gives you the tools to do that. It's a genuinely differentiated offering in a marketplace full of traditional carriers.

Potential drawbacks: This is not a hand-holding experience. If your IT team isn't comfortable working with APIs or you're looking for a provider that will manage everything for you, Bandwidth probably isn't the right fit. They're built for teams that want control, not convenience.

SIPPIO

SIPPIO isn't a carrier in the traditional sense. They're an OC-native platform built primarily for the channel, giving MSPs and resellers a way to deploy and manage Operator Connect across multiple clients.

Best for: MSPs and channel partners deploying Operator Connect at scale across their client base.

Strengths: SIPPIO's platform is purpose-built for Operator Connect, with fast provisioning and multi-tenant management designed for partners juggling dozens of deployments. They also support Zoom Phone alongside Teams, which is useful if your client base isn't standardized on a single platform. The infrastructure runs on Azure, so there's no proprietary network to worry about.

Potential drawbacks: End-customer brand recognition is limited. If you're an IT director looking for a direct relationship with your voice provider, SIPPIO probably isn't on your radar, and isn't trying to be. Support routes through the partner channel, so your experience depends heavily on the MSP you're working with rather than SIPPIO itself.

Granite Telecommunications

Granite is a $1.85 billion telecom provider that has built its business around serving multi-location enterprises with consolidated billing and account management. They joined the Operator Connect program in January 2024.

Best for: Multi-site US businesses that want a single vendor and a single bill across all locations.

Strengths: Granite serves more than two-thirds of the Fortune 100 and manages over 1.75 million voice and data lines across 650,000+ locations. That scale is their selling point. If your organization has dozens or hundreds of sites and you're tired of managing multiple carrier relationships, Granite's consolidated approach is designed to solve that problem. They also offer both Operator Connect and Direct Routing for Teams.

Potential drawbacks: Granite is relatively new to the Operator Connect program, and there's limited public information about their OC-specific offering, including pricing. They do not offer GCC High, so government contractors with compliance requirements in that space will need to look elsewhere.

Honorable Mentions

A few other certified partners worth noting, depending on your specific requirements:

Intrado is enterprise-focused with a cloud-first approach to voice. Fusion Connect targets the mid-market with a managed services and UCaaS-forward model. Tata Communications offers global reach across 60+ countries and holds Microsoft's "Preferred" Operator Connect partner designation. NTT Data covers 40+ countries with enterprise-grade SLAs and has been leaning into Copilot automation for Teams workflows.

Need Help Deciding?

Most IT directors don't choose wrong on price. They choose wrong on support and fit.

If you're working through this decision and want a straight answer about whether Atlantech makes sense for your organization, or who does if we're not the right fit, just reach out. We'll give you an honest read, not a sales script.

Your first month is free, with no setup or porting fees. Check out our Operator Connect Buyer's Guide for more information, or reach out and talk to us.