Outbound Attestation
Voxtelesys signs all outbound calls originating from our network with a STIR/SHAKEN passport, as defined by RFC 8224 (STIR), RFC 8226 (PASSporT), and RFC 8588 (SHAKEN). Signing is performed automatically on every call — no configuration is required on your end.
The passport includes an attestation level that communicates to downstream carriers and terminating providers how much Voxtelesys was able to verify about the call's origin. This level directly influences how the receiving carrier and end-user device treat the call, including whether it displays a "Verified" or "Spam Likely" label on the recipient's phone.
Attestation Levels
| Level | Name | Description | Scenario |
|---|---|---|---|
| A | Full Attestation | Voxtelesys has verified the identity of the calling party and confirmed that they are authorized to use the presented number | Call from owned phone number |
| B | Partial Attestation | Voxtelesys has verified the call originated from a known customer, but cannot confirm that the customer is authorized to use the specific number presented | Call from non-owned or verified number |
| C | Gateway Attestation | Voxtelesys can only verify where the call entered our network, but cannot authenticate the original calling party or their right to use the number | Not applicable |
How Attestation is Determined
Voxtelesys assigns attestation based on the relationship between the calling party and the number being presented as the caller ID.
Full Attestation (A)
A call receives Full Attestation when the number used as the caller ID is hosted on the Voxtelesys network. Because Voxtelesys both owns the number and knows the account it belongs to, it can fully verify that the customer has the right to present that number.
This is the highest attestation level and results in the best outcomes for call delivery and caller ID display.
Partial Attestation (B)
A call receives Partial Attestation when the number used as the caller ID was not obtained through Voxtelesys — for example, customers using the Voxtelesys voice stack but bringing their own numbers. Voxtelesys can confirm the call originated from a known customer on our network, but cannot independently confirm that customer's authorization to use a number we did not provision.
Gateway Attestation (C)
All calls originating from the Voxtelesys network are associated with a known customer account, so Gateway Attestation (C) is not applicable to outbound calls from our platform.
Why Attestation Matters
Attestation level is one of the primary signals used by terminating carriers and analytics platforms (such as CNAM and call reputation services) to determine how to label an inbound call on the recipient's device.
- Level A calls are most likely to display as "Verified" on supported devices and least likely to be flagged as spam.
- Level B calls may display without a verified badge and are subject to greater scrutiny by downstream analytics.
- Level C calls carry the least verification weight and are more likely to be treated with suspicion by terminating carriers.
To maximize deliverability and minimize the risk of spam labeling, use numbers hosted directly on the Voxtelesys network. These calls receive Full Attestation (A).