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Glossary · Carriers and wholesale

BYOC (bring your own carrier)

In one sentence

BYOC (bring your own carrier) means connecting a communications platform, such as Microsoft Teams, a cloud contact centre or a voice-agent platform, to the carrier of your choice over a SIP trunk, instead of using the telephony the platform sells.

Also known as : BYOC · bring your own carrier · bring-your-own-carrier

What is BYOC?

Many communications platforms resell their own telephony. You open an account, buy numbers in the dashboard and the minutes appear on the platform’s invoice. That is convenient, but it ties you to that vendor’s coverage, prices and number stock. BYOC, bring your own carrier, flips this around: the platform keeps doing what it is good at (interface, routing, recording, reporting), while calls come in and go out through a carrier you pick.

You will meet BYOC in several kinds of product:

  • Microsoft Teams Phone, through Direct Routing;
  • cloud contact centre software;
  • voicebot and voice-agent platforms such as Vapi, Retell or ElevenLabs, which need real phone numbers to take and make calls.

How it works

  1. The carrier provides a SIP trunk: server address, credentials or allowed IP addresses, supported codecs.
  2. You add the trunk in the platform, sometimes through an intermediate session border controller, as Teams requires.
  3. Numbers, new or ported, stay with the carrier. Each DID is mapped to a user, a queue or an agent in the platform.
  4. Outbound calls leave the platform over the trunk, and the carrier handles termination to the person being called.

Most problems come from mismatches: numbers not in international E.164 format, no codec in common, DTMF sent the wrong way, or a caller ID the carrier will not accept.

Example

A London start-up builds AI agents that answer phone calls for dental practices across the UK and Ireland. Its voice-agent platform sells numbers, but not geographic numbers in every area code its clients use, and practices want to keep the number printed on their letterheads. The start-up switches to BYOC: it takes a SIP trunk from a European carrier, ports each practice’s number and registers the trunk in the platform. Practices keep their numbers, and the start-up sees all call costs on one carrier bill.

BYOC at Universal Telecom

Our wholesale offer includes a Spanish SIP trunk designed for BYOC with voice-agent platforms, plus local numbering in many countries (see coverage). To connect your own phone system instead, the SIP trunk page covers the business offer.

Frequently asked questions

Is BYOC the same as Teams Direct Routing?

Direct Routing is Microsoft's name for BYOC in Teams Phone: a certified SBC links Teams to a SIP trunk from the carrier you choose. Operator Connect is a managed alternative where the carrier sets up that link for you.

Why use BYOC instead of the platform's own numbers?

To keep numbers you already have, get local numbers in countries the platform covers poorly, control call costs and avoid being locked in if you ever change software.

What do I need to set up BYOC?

A SIP trunk from your carrier (server address, credentials or allowed IPs, supported codecs), numbers on that carrier, and access to the platform's trunk settings. Test inbound, outbound, caller ID and DTMF before moving live traffic.

Related terms

  • SIP trunk

    A SIP trunk is a voice-over-IP connection between a business phone system and a carrier. It replaces ISDN lines and carries calls and numbers over your internet connection.

  • Call termination

    Call termination is the final leg of a phone call: carrying it across the called person's network, which charges the originating carrier a termination fee. The cost depends on the country, the line type (landline or mobile) and the route used.

  • SBC (session border controller)

    A session border controller (SBC) sits at the edge of a network and controls SIP calls going in and out: it filters traffic, hides the internal network, handles NAT and can transcode or encrypt calls.

  • CCaaS

    CCaaS (contact centre as a service) is cloud-hosted contact centre software. It receives calls, emails and messages, routes them to agents, manages queues and gives supervisors live dashboards and reports, on a per-agent subscription.

  • UCaaS

    UCaaS (unified communications as a service) brings business telephony, video meetings, instant messaging and often file sharing together in one cloud service, billed per user and used from desk phones, computers or mobiles.

  • DID (direct inward dialling)

    A DID (direct inward dialling) number, called a DDI in the UK, is a public phone number that rings a specific extension, team or call flow directly, without passing through a switchboard.

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