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Underlying Carrier (ULC)

Underlying Carrier (ULC) is a third party vendor/carrier (upstream, or downstream from Bandwidth, depending on the call direction). This term would be commonly heard in the context referring to outbound calling/termination. For example, one might say, “We’ve removed a ULC from the call route who was providing PDD (Post Dialing Delay)”.


How Bandwidth is Involved with ULCs

Bandwidth is considered an underlying carrier for businesses such as Google and Skype since we provision voice services that power products like Google Voice and Microsoft Skype for Business. This voice service is just one of the many communication solutions that Bandwidth provides through our APIs. The APIs that Bandwidth provides sit atop one of the largest All-IP Voice Networks in the nation that we own and operate. Bandwidth also provides services for messaging, 9-1-1 access, and phone numbers. By providing voice services along with additional integrations, Bandwidth is able to meet the needs of growing businesses, both large and small, as they build products that connect people.


What Are the Benefits of Bandwidth as an Underlying Carrier (ULC)

Since Bandwidth owns and operates one of the largest All-IP Voice Networks in the nation, our customers are able to enjoy fast, reliable communication services, scalability, and cost savings. Bandwidth offers our customers world class support with a 24/7 NOC team that is available to address issues as soon as they arise. In addition, Bandwidth’s communication services are built to scale. Whether you are a small start-up or an enterprise giant, Bandwidth services can scale to meet your needs. In addition, partnering with Bandwidth lets you avoid dealing with a middleman. This means more cost savings for your business while allowing you to connect with a service you trust. Bandwidth has mastered communication software, so you can focus on what matters most to you.



Where We Talk About ULCs

On our site

  • The Bandwidth Advantage: Why It Pays to Own the Network
  • Bandwidth and BlueLight Revolutionize Campus Safety with Smarter Phone Calls
  • Bandwidth Messaging Services
  • In our downloads

  • Patronus Gives Users a Modern Way to Dial 9-1-1 Thanks to Bandwidth
  • Bandwidth Messaging Services


    Terms Related to ULC

  • Termination/Outbound Calling
  • Post Dial Delay (PDD)
  • Phone Call API / Voice Calling API


    Return to full list

    Our lawyers have asked us to remind you that, in the event of any conflict between these defined terms and the defined terms included in any agreement between you and Bandwidth, the agreement controls.

    “Bandwidth” refers to Bandwidth Inc. and/or CLEC, LLC.