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Compare SIP trunk providers and connect your IP PBX to reliable VoIP. Port numbers, cut line costs, and add channels on demand. Get a free consultation.
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SIP trunking connects your IP PBX to the public phone network over the internet instead of physical T1 or analog lines. The hard part is not the technology, it is choosing a provider that runs its own network, protects you from fraud, and answers the phone when you call.
A SIP trunk is the modern replacement for a T1 trunk. Instead of buying physical lines from a telco, you connect a set of voice channels to your VoIP or IP PBX over your internet connection. SIP, the Session Initiation Protocol, sets up and tears down each call. Your phone numbers and DIDs attach to the trunk, and in most cases your existing numbers port over so nothing changes for the people who call you.
The recurring fee for copper lines drops once you move to SIP, and additional DIDs cost far less than physical lines.
Competition has pushed per-minute and long-distance rates down, many plans bundle calling, and international rates cost less.
A SIP trunk is not tied to a physical address. Move offices or open a second site and your numbers come with you.
Add local or toll-free numbers in other area codes quickly, so customers and citizens reach you on a local number.
Calls arrive over IP end to end, which removes analog-to-IP gateways and often means cleaner audio.
Adding channels is a configuration change, often same-day, instead of weeks of carrier lead time for physical lines.
The decision is not about the lowest per-minute rate. These factors separate a provider you can rely on from one that costs you in outages and fraud.
A SIP trunk is exposed to the internet. Toll fraud can run up thousands overnight, so active anti-fraud monitoring is not optional.
Many providers resell trunks from someone else and cannot fix problems at the source. Choose one that runs its own network.
Look for competitive rates on genuine business-class service, and be skeptical of pricing too good to hold up under real call volume.
Confirm the provider can port every one of your numbers, not just the easy ones. Coverage varies by region and number type.
When a trunk has trouble you need a person, not a ticket queue that closes at 5 p.m. True IP provides 24/7 on-call support.
Voice quality depends on the connection the trunk rides on. We recommend a dedicated voice path or quality-of-service rules that protect voice from data congestion, and we confirm your firewall passes SIP traffic correctly.
Old copper usually feeds a rigid hardware PBX. You can add a gateway, but most organizations gain more from a modern IP PBX or a hosted platform. We tell you honestly which path fits.
We provision the trunk, port your numbers, test the routing, and support it directly with a local team when something needs attention.
SIP trunking rarely stands alone. The same move often touches your PBX, cabling, fax lines, and the analog circuits running elevators and alarms.
Skip the on-site box entirely with a managed cloud phone system.
Learn more →Cover the life-safety circuits SIP trunks do not, including elevators and fire alarms.
Learn more →The structured cabling and network engineering underneath your voice path.
Learn more →One vendor across every location, with numbers that move when you do.
Learn more →Department routing and reach across annexes and remote offices.
Learn more →A SIP trunk is a set of voice channels that connect your IP PBX to the public phone network over the internet, replacing old T1 or analog lines. Each channel carries one concurrent call, your phone numbers attach to the trunk, and your existing numbers can usually be ported over.
Look past the per-minute rate. Confirm the provider runs its own network with active fraud protection, can port all of your numbers, offers business-grade quality rather than consumer pricing, and gives you direct support with real availability. A provider that resells someone else's trunks cannot control quality or fix problems at the source.
In most cases, yes. Existing numbers can be ported to the SIP trunk so nothing changes for callers. Porting coverage varies by region and number type, so confirm with your provider that every number you have can move.
If you already run an IP PBX, a SIP trunk connects to it directly. If you have an older hardware PBX, you can add a gateway, but most organizations get more value by upgrading to a modern IP PBX or a hosted platform. We help you decide which path fits.
No. SIP trunks carry your phone system traffic, not the analog circuits behind elevators, fire alarms, and some fax machines. Those need a dedicated analog line replacement. Our POTS replacement service covers those life-safety and compliance circuits.
Adding channels is a configuration change, often handled the same day, instead of the weeks it takes a carrier to install physical lines. You size the trunk to your concurrent call volume and scale it as your call load changes.
Get a free consultation and we will size a trunk to your real call volume.