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Trusted Voice Provider

Migrate smoothly to the leading Lumen voice alternative 

Sinch owns and operates the voice network that Tier-1 carriers rely on, and our expert team is helping Lumen customers navigate their next steps after the end of sale – this ensures there are no surprises come renewal date.

  • Works with Microsoft Teams, Genesys, Webex, and Five9 

  • Keep your numbers: we handle transfers, vanity numbers, and fraud protection directly

  • Test us and move on your own timeline, with no disruption to your current Lumen agreements

Talk to our voice experts
Image for Migrate smoothly to the leading Lumen voice alternative 
We power communication for the world's largest companies

Why choose us

Four reasons enterprises move their traffic to Sinch

Now that Lumen has stopped selling new enterprise voice, it’s time to plan for a new home for your voice traffic. Sinch proves to be the top choice for four reasons:

Not a resold trunk. You get direct control over routing, quality, and troubleshooting – which is why other carriers hand us their traffic.

Your number transfers get a named team, not a shared support queue. We’re an officially registered toll-free provider, so we handle transfers, vanity numbers, and fraud protection directly.

99.99% uptime on SIP Trunking, backed by a network operations center staffed 24/7. We also provide the compliance layer enterprise voice needs: STIR/SHAKEN caller ID authentication, E911, Kari’s Law and RAY BAUM’s Act support, and TLS/SRTP encryption.

We’re investing across enterprise telephony, contact center, application-centric voice, and agentic AI voice. It’s a core business, and it’s growing.

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“We rely on Sinch for stability, scale, and support across every channel we deliver. Voice, messaging, numbering, dynamic E911 — practically everything we offer runs through Sinch. The platform is rock-solid.“
  • SIP Trunking
  • Numbers
  • Dynamic E911
1,200+
businesses served
20,000
numbers under management
Evan Huff CEO and Founder at Vested Networks
Read the customer story
How Vested Networks increases reliability and trust with Sinch

Voice network Leader

Tier 1 carriers hand us their traffic

There’s no one upstream between your call and our network. Sinch owns and operates the largest and most powerful independent voice network in the U.S. – built for the carriers, service providers, and enterprises that can’t afford a voice call to fail. Our geo-redundant network ensures extensive reach, secure connections, and the highest service quality. 

Image for Tier 1 carriers hand us their traffic
250 billion
minutes carried per year
160 million +
phone numbers powered by our network
99.99%
Guaranteed uptime, SIP Trunking
Since 2004
Operating our own U.S. voice network

Emergency Services

Sinch delivered 52+ million 911 calls last year

We operate the 911 network that connects to 6,300+ Public Safety Answering Points (PSAPs), and have a dedicated emergency services team to ensure quality. This is why our E911 services hold up for:

  • Hospitals

  • Contact centers

  • Government offices

  • Financial branches

  • Multi-location businesses

  • Large enterprises

Image for Sinch delivered 52+ million 911 calls last year

Bring your own carrier

Switch carriers while keeping Teams, Genesys, Webex, or Five9 intact

Bring Your Own Carrier (BYOC) separates the carrier from your platforms, so you can keep your numbers and put your per-minute costs on a dedicated, predictable invoice. 

Running something more specialized? Tell us what’s in place and we’ll advise whether it’s a carrier swap or a project that needs more planning.

  • We’re one of only three Microsoft Teams certified and integrated E911 providers, making setup easy

  • Also supports Zoom, Cisco, NICE, 3CX, and on-premises PBX via gateway 

  • Centralized management and consistent emergency calling across locations

  • Ready for AI-powered and agentic voice when you are 

Image for Switch carriers while keeping Teams, Genesys, Webex, or Five9 intact
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Sinch is a 2026 Gartner® Magic Quadrant™ Leader for CPaaS
Read the Gartner Report

Run a free test

Test real calls with Sinch before you decide

Instead of waiting until your Lumen contract ends before you understand your next move, test Sinch risk-free. We’ll help you run real traffic across our network, while your current service stays exactly where it is until you decide.

One date sets everything else, whether you’re planning a transition now or booking a check-in for later.

Point a slice of real traffic at the Sinch network and judge call quality, reliability, and operational fit yourself.

A dedicated team maps your locations and number inventory into a porting, testing, and cutover plan. No surprises mid-migration.

Numbers port with no service interruption. Your platform never moves.

Ask about running a test
Image for Test real calls with Sinch before you decide
“Sinch has truly empowered our platform by making it easy to manage both SMS and voice. Our clients appreciate the flexibility and seamless callback features that enhance the customer journey.“
100s
of phone numbers managed
50+
projects onboarded
Oscar Orozco Senior Voice Engineer at LiveVox
Read the customer story

Frequently asked questions

No, and we won’t ask you to break an active contract. Lumen has said it will support existing agreements. The reason to start now is practical: porting, testing, and cutover take planning, and it’s easier to do that before a renewal date sets the timeline for you.

Yes. Numbers transfer through the standard portability process, and because we’re an officially registered toll-free provider, we handle transfers, vanity numbers, and fraud protection directly. A dedicated team runs the transfer to keep disruption down. 

In most cases, yes. Sinch works with Teams, Genesys, Webex, Five9, Zoom, NICE, and Cisco, and connects to Teams calling through Operator Connect. Depending on your architecture, you keep the calling or contact center platform you already run and change only the carrier underneath. More specialized legacy setups need extra planning. 

Not one-for-one. If you pooled calling capacity across locations, or ran legacy and IP lines together while migrating site by site, this is a bigger project than a standard carrier swap. Raise it in the first conversation and we’ll scope it honestly rather than discover it halfway through. 

Fair question to ask anyone right now. Our U.S. voice business has run since 2004, carries roughly 250 billion minutes a year across 160 million+ numbers, and delivered over 52 million 911 calls in 2025. Voice is a growth area and an area of active investment for Sinch. 

It depends on locations and number volume, which is why we scope before quoting a timeline. A single-site trunk replacement is nothing like a multi-country port of tens of thousands of numbers. What we commit to is a parallel evaluation you can start now, and a dedicated team on the port itself. 

99.99% on SIP Trunking, with a network operations center staffed 24/7. 

References to Lumen’s end of sale reflect Lumen’s own public announcements. Nothing here is advice to break an existing contract. Lumen, Microsoft Teams, Genesys, Webex, Five9, Zoom, Cisco, and NICE are trademarks of their respective owners, used for identification only.