FCC LICENSED CARRIER ·499 FILER ·STIR/SHAKEN CERTIFIED
SIPNEX
Services · SIP Trunking

SIP trunks for operators who dial like they mean it.

Buy direct from the carrier — not a reseller marking up someone else's trunk. Unlimited channels, A-level attestation signed with our own STIR/SHAKEN certificate, and support from engineers who know what sip.conf is.

Request Dialer-Grade Trunk → See Pricing
  • Who it's for: dialer and contact-center operators pushing serious outbound volume.
  • What you get: unlimited channels, direct A-level attestation, DIDs live in minutes.
  • How fast: a live trunk within 24 hours of a signed agreement.
Definition

What does a SIP trunk provider do?

A SIP trunk provider connects your phone system to the public telephone network over the internet. It carries your calls, issues your phone numbers, and signs your caller ID. Some providers are licensed carriers that run their own network. Others are resellers who mark up a carrier's trunk. SIPNEX is the carrier: FCC-licensed, a registered 499 filer, with our own STIR/SHAKEN certificate.

The provider you pick shows up in your numbers, not your contract. Attestation moves answer rates. Channel caps decide how hard your dialer can push. Provisioning speed sets how fast a new campaign gets numbers. So the first question is not the rate — it is whether you are buying from the network or from a middleman.

What you get

Carrier-grade, not reseller-grade.

Unlimited concurrent channels

No artificial caps. Your trunk scales with your instance — not ours. Run 10 or 10,000 concurrent calls.

Direct A-level STIR/SHAKEN

We sign every outbound call with our own SP-KI certificate. Not downstream, not rewrapped. Direct A-level from the originating carrier.

Instant DID provisioning

Provision local, toll-free, and vanity numbers across all North American area codes. New DIDs active in minutes, not days.

VICIdial-native configuration

We provide tested sip.conf templates, codec recommendations, and direct support from engineers who run VICIdial themselves.

24-hour trunk provisioning

From signed agreement to live trunk in one business day. Complex porting takes longer, but your initial setup doesn't wait.

Transparent per-minute pricing

Published rates. No quote-gated pricing games. You see what you pay before you talk to anyone.

Side by side

Carrier vs reseller: two kinds of SIP trunk provider.

Every SIP trunk provider either runs the network or resells someone else's. Here is what that difference means, line by line.

CAPABILITY SIPNEX TYPICAL RESELLER
FCC-licensed carrier ✓ Direct Reselling upstream
STIR/SHAKEN attestation A-level (own cert) B-level (inherited)
Concurrent channel limit Unlimited 10–50 typical
DID provisioning speed Minutes 1–5 business days
VICIdial support Native (we run it) Generic / unsupported
Pricing transparency Published rates Quote-gated
Trunk provisioning 24 hours 5–10 business days
Uptime SLA 99.999% 99.9% if offered
Buyer's checklist

How to choose a SIP trunk provider.

Six checks separate a carrier from a middleman, and none of them require a sales call. A provider that hides its rates behind a quote form is telling you something — compare our published SIP trunk rates first.

  1. Verify carrier status. Look the provider up in the FCC Form 499 filer database and the Robocall Mitigation Database. Both are public, and neither can be faked.
  2. Ask who signs STIR/SHAKEN. Direct A-level attestation requires the provider's own SP certificate, not one borrowed from an upstream.
  3. Check the concurrent-channel cap. Ask what happens at 50 channels, then at 500. The answer tells you whose network you are really on.
  4. Time the provisioning. Ask how long a new trunk and a new DID take. Minutes point to a carrier; a week points to a ticket queue.
  5. Confirm codec and platform support. G.711, G.729, and Opus should all be on the menu, along with your PBX or dialer platform.
  6. Test the support line. Ask one technical question before you sign. Whoever picks up is your support experience from day one.
Beyond the spec sheet

Where a SIP trunk fits in your stack.

A trunk is the voice artery of whatever communication platform you run. Register your PBX system, predictive dialer, or contact center against SIPNEX and the same trunk carries inbound and outbound traffic — DIDs ring straight into your queues while your agents dial out on caller IDs you control, signed with A-level attestation.

This is elastic SIP trunking in the literal sense: capacity follows your call volumes instead of a channel count you ordered last quarter. Campaigns ramp, seasonal spikes hit, and the trunk flexes in real time — no change orders, no waiting on a carrier to “add lines,” because the only limits are your own server resources and bandwidth.

Whatever sits above the trunk — a PBX, a dialer, a unified communications suite — every call that touches a real phone number leaves it over SIP. That PSTN leg, not the app, determines whether your calls connect and how they are labeled.

Call quality is where SIP trunking services actually separate. Codec choice matters — we recommend G.711 for the cleanest audio — but so does who answers when something degrades. Our support team is the same group of engineers who run high-volume dialing operations, so when you compare providers, compare who picks up the phone, not just the spec sheet.

Know what you're buying

Carrier, reseller, or aggregator?

Licensed carrier (own network)

Runs its own network and holds its own FCC authorization and STIR/SHAKEN certificate. Your trunk, your numbers, and your attestation come from one company. SIPNEX operates at this layer — the same network behind our wholesale VoIP carrier service.

Reseller

Buys trunk capacity from a carrier and rebrands it. Pricing carries a markup, channel caps are common, and support tickets travel through a company that cannot touch the network. Attestation is whatever the upstream grants — typically B-level.

BYOC aggregator

A software platform that lets you bring your own carrier trunk into its cloud — the BYOC model. Useful when your team is committed to a platform's tooling, but the platform still needs a carrier underneath, and its fees stack on the carrier's rate.

Frequently asked

About SIP trunking with SIPNEX.

What is a SIP trunk?
A SIP trunk is a virtual phone line that connects your phone system (PBX, dialer, contact center) to the public telephone network over the internet using the SIP protocol. Instead of physical copper lines, your calls travel as data packets. The trunk is the connection between your system and the carrier — in this case, SIPNEX.
How many concurrent calls can a SIP trunk handle?
On SIPNEX, there is no artificial concurrent channel limit at the trunk level. Your capacity is determined by your own server resources and internet bandwidth, not by a cap we impose. Most resellers limit you to 10–50 concurrent channels per trunk — we don't.
What codecs do you support?
G.711 (ulaw/alaw) for highest quality, G.729 for bandwidth-constrained environments, and Opus where supported. For VICIdial deployments, we recommend G.711u as the primary codec with G.729 as a fallback.
Do I need special equipment to use SIP trunks?
You need an IP-capable PBX, dialer, or softswitch with a reliable internet connection. VICIdial, FreePBX, Asterisk, FreeSwitch, 3CX, and most modern platforms support SIP trunking natively. We provide configuration templates for VICIdial and will assist with other platforms.
How fast can I get a SIP trunk from SIPNEX?
24 hours from signed agreement to live trunk, typically. We provision your initial DIDs and trunk credentials within one business day. Number porting from another carrier takes longer (7–14 business days is standard) but you can start dialing on new DIDs immediately while the port completes.
What is STIR/SHAKEN and why does it matter for my SIP trunk?
STIR/SHAKEN is a caller ID authentication framework mandated by the FCC. Your outbound calls are cryptographically signed by the originating carrier with an attestation level (A, B, or C). A-level means verified caller — best answer rates. SIPNEX signs with our own SP-KI certificate, giving you direct A-level attestation. Most resellers can only provide B-level because they don't hold their own certificate.
Can I switch my SIP trunks to SIPNEX without changing phone numbers?
Yes — your numbers come with you. Local, toll-free, and vanity numbers port across North America while your trunk stays live, and you can start dialing on new SIPNEX-provisioned DIDs immediately while the port completes in the background. Porting logistics and timelines are covered on our DID numbers page.
What kind of support does SIPNEX offer?
Phone and email support from engineers who run VICIdial and high-volume dialing operations themselves. When you call us about a sip.conf issue, the person answering knows what that means without escalation. We don't have a generic tier-1 helpdesk — your first contact is the person who can fix it.
How can you tell if a SIP trunk provider is a carrier or a reseller?
Ask one question: does the provider sign calls with its own STIR/SHAKEN SP certificate, or does it inherit attestation from an upstream carrier? Resellers inherit. SIPNEX signs with its own certificate, holds direct FCC authorization, and files its own regulatory paperwork — the checks are laid out on our FCC licensing page.
Do I have to move all my traffic to SIPNEX at once?
No. Running trunks from two providers side by side is standard practice — most PBXs and dialers can register multiple trunks and route between them. Operators typically point a slice of outbound traffic at the new trunk, compare answer rates and quality against the incumbent, then shift volume as the numbers come in. Your existing numbers port in the background while you dial on new SIPNEX DIDs.
Do I need a SIP trunk if I already have VoIP phone service?
They solve different problems. A VoIP phone service sells you the whole system — handsets, apps, voicemail, and the carrier connection bundled together. A SIP trunk is only the carrier connection, for operators who run their own PBX, dialer, or contact center platform. If you own the phone system and just need it to reach the telephone network, a SIP trunk is the piece you are shopping for.

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Get a trunk in 24 hours.

Tell us your platform, your volume, and how many concurrent channels you need. We'll quote you same-day and provision next-day. Reselling or pushing serious monthly minutes? Start with SIPNEX as your wholesale VoIP carrier instead.

Request Dialer-Grade Trunk → See Pricing
Or call direct: (833) 665-2220