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CallTower Solutions Center


The US Federal Communications Commission (FCC) has taken action to limit the ability of robocalls to scam consumers and businesses through rules to address caller ID spoofing.  The FCC is regulating this process using STIR/SHAKEN.


What is STIR/SHAKEN? - STIR/SHAKEN uses digital certificates, based on common public key cryptography techniques, to ensure the calling number of a telephone call is secure. In simple terms, each telephone service provider obtains their digital certificate from a certificate authority who is trusted by other telephone service providers. The certificate technology enables the called party to verify that the calling number is accurate and has not been spoofed.  The process is similar to the security process for HTTPS secured websites.  The originating telephone service provider attests to the level of validation that can be guaranteed on each call.


There are 3 levels of attestation that can be applied to a call:

  • Full or “A” Attestation:  The service provider knows the customer and their right to use the phone number.
  • Partial or “B” Attestation:  The service provider knows the customer but not the source of the phone number.
  • Gateway or “C” Attestation:  The service provider has originated the call onto the network but can’t authenticate the call source e.g., international gateway.


The new TRACED Law (STIR/SHAKEN technology implementation) took effect on June 30, 2021. There will be no immediate change in how calls will be processed, as there continues to be extended implementations industry-wide.  Changes to handling calls based on STIR/SHAKEN attestation information will be phased in over different timeframes for each US telecommunications provider.   


Please note:

  • CallTower is currently signing and providing attestation on outbound calls
  •  CallTower will provide Full, or A level Attestation on outbound calls utilizing CallTower provided numbers.
  • Outbound customer calls using non-CallTower provided numbers will be signed with Partial, or B level Attestation.
  • CallTower will communicate any changes to how we handle inbound calls based on attestation level before they take effect.


What does this mean right now?

CallTower services will not change at all.  There are no feature changes and no action on your side is needed.

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