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STIR/SHAKEN for outbound dialers

How STIR/SHAKEN attestation works, why your answer rates depend on it, and how to get attestation A.

STIR/SHAKEN is the FCC's caller-ID authentication framework. As of 2026, it's mandatory for US carriers and dictates whether your calls show up as legitimate or get tagged as spam.

What it does

When you place an outbound call, your carrier signs the call with one of three attestation levels:

  • A — Full attestation. Carrier verified you, the calling number is yours, and you have the right to use it.
  • B — Partial. Carrier verified you and the gateway, but not the number itself.
  • C — Gateway. Carrier just passes it through; can't verify the originator.

Receiving carriers see the attestation and decide what to do:

  • A → call rings normally
  • B → may show "Likely Spam" or "Scam Likely" warnings
  • C → high probability of being silently blocked or marked spam

What this means for answer rates

Operators we work with see:

  • A attestation: 12-15% answer rates on cold lists
  • B attestation: 6-8%
  • C attestation: under 3% — campaigns die

The single highest-leverage thing you can do for outbound dialing answer rates in 2026 is get on A.

How to get attestation A

You need three things:

1. A SIP carrier that supports A-attestation

Not all do. Confirmed support: Bandwidth, Telnyx, Twilio (Elastic SIP), Inteliquent, Voxbeam (US side), Ringbridge.

Some smaller carriers route through aggregators that drop attestation to B or C. Ask your carrier directly: "What attestation level do my outbound calls receive?"

2. A DID you own

Caller ID must be a phone number that:

  • You purchased + provisioned through your A-supporting carrier
  • You actually answer (or route to voicemail/IVR)

Spoofing a number you don't own → automatic B/C, plus TRACED Act exposure.

3. KYC / account vetting

Your carrier needs to know who you are — business name, address, EIN, beneficial owners. Reputable carriers require this before A.

Per-campaign caller ID

Set caller ID per campaign in VICIdial → Campaign → Campaign CID.

Common patterns:

  • One DID per campaign — keeps reputation cleanly attributable
  • Local-presence rotation (matching outbound CID to lead's area code) — controversial; some carriers allow it, some don't, and reputation tracking is harder

Reputation management

Even at attestation A, your numbers can get flagged if:

  • Drop rate exceeds 3% on a campaign using that DID
  • Consumers mark the number as spam
  • Volume per number is too high

Industry guideline: don't exceed ~50 calls per minute from a single DID. Rotate DIDs by campaign or by hour.

Reputation services

Caller ID reputation is tracked by 3rd parties (TNS, First Orion, Hiya). They feed mobile carrier "Spam Likely" warnings. You can register your DIDs with them — fees apply, sometimes worth it for high-volume campaigns.

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