Webinar on STIR/SHAKEN & Call Blocking – What lead gen call centers need to know

STIR/SHAKEN and call blocking are two highly current hot topics on the minds of outbound call center operators. And for good reason.

STIR/SHAKEN is a set of industry initiatives designed to limit robocalls. The new rules and procedures will have a huge impact on your lead gen call center due to the increased risks of call blocking. Will you still be able to reach new customers?

To help all of us understand and prepare for STIR/SHAKEN, we hosted a webinar with industry expertsMichele Shuster [Founding Partner, Mac Murray & Shuster LLP, Ryan Thurman [Director of Sales & Marketing, Contact Center Compliance], and Nima Hakimi [CoFounder and CEO, Convoso]. During this discussion we learned what STIR/SHAKEN is, what to expect over the coming years, and how businesses can ensure full compliance and success through these changes.*

WATCH THE PRESENTATION in this video. You can read a summary below.

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Webinar Summary: STIR/SHAKEN & Call Blocking – What lead gen call centers need to know


STIR/SHAKEN stands for Secure Telephone Identity Revisited/Signature-Based Handling of Asserted Information Using toKENs. It is a call authentication network that works to limit robocalls and the spoofing of caller IDs to trick consumers. 

To do so, originating carriers assign each call one of three attestation ratings. When the terminating carrier receives the call, they can then use this signature to determine if the call is valid and if it should reach the intended consumer. 

Attestation Ratings

STIR-SHAKEN 3 Attestation Ratings

The three attestation ratings include:

  • A – Full Attestation, meaning the carrier has confidence in the identity of the caller and the caller’s right to use the caller ID information presented.
  • B – Partial Attestation, meaning the carrier has confidence in the identity of the caller but not the caller’s right to use the caller ID information presented.
  • C – Gateway Attestation, meaning the carrier cannot certify the identity of caller or their right to use the caller ID information presented. The carrier merely acted as a gateway to place the call on the network.

Michele Shuster, founding partner at MacMurray & Shuster, said these ratings are based on two factors. First, the level of confidence the originating carrier has in knowing who is making the call. Second, if the caller has the authority and ability to use the caller ID information associated with the call.

What do these attestation ratings mean?

An A rating shows the signing authority is fully confident in your use and authority, Shuster said. A B rating means the carrier knows who you are, but isn’t certain that you should be using the caller ID attached to the call. Getting an unwarranted B rating is a common problem for some callers on the STIR/SHAKEN network and is still being addressed by regulators.

“A really good example of that is call centers or enterprise call enterprise calling that occurs in call centers. The call centers will have various carriers,” Shuster said. “And depending upon whether your carrier that you’re initiating is the same that will be carrying that call will largely affect whether you’ll get a full or a partial attestation.”

C or Gateway Attestations show that carriers know which gateway the call was initiated through, but not the authority or identity of the caller. This rating is common for international calls.

What is the timeline for STIR/SHAKEN?

Deployment for these regulations began in 2019 and all major carriers are currently using some form of the network, Shuster said. 

On March 31, 2020, the FCC also announced a Further Notice of Proposed Rulemaking, which involves who is going to be able to sign calls beyond the current limited entities. Originating and terminating carriers now have to deploy, if they haven’t already. 

STIR/SHAKEN has a full deployment deadline of June 21, 2021, though smaller and rural carriers may receive extensions.

What are the benefits and limitations?

During the webinar, Shuster outlined four main benefits and limitations to the new regulations.


One important limitation to recognize, Shuster said, is that the attestations cannot determine if a call is wanted or legal.

“One of the things that I think people are usually surprised to hear is that STIR/SHAKEN is not in any way based on the legality of the call,” she said. “What it does is allow us to be sure who is making the call and whether they have the ability to use caller identification that they’re using.”


If calls are receiving large numbers of complaints or being blocked by analytics companies, STIR/SHAKEN helps determine the caller and prevent illegal calls more effectively. Calls with C ratings are treated as suspect, while A and B level callers can be traced and prosecuted more easily.


Shuster noted that STIR/SHAKEN is IP-based, so rural carriers and those using legacy equipment such as TDM or copper lines won’t be affected.

Caller IDs

If caller ID values are obtained from one carrier and used to place calls on another carrier, callers will likely receive a B rating. Call centers often struggle to get A ratings for this reason, a problem the FCC is still working to resolve.

What can you do to ensure STIR/SHAKEN compliance?

To make sure your calls get through to your leads, there are six main strategies that you can use to support compliance. 

Inventory your telephone numbers

Before making calls, it’s important to know which numbers you’re using to make calls and if these numbers are going to cause problems. Each carrier uses its own analytics to determine if a call should be blocked, some more aggressive than others. Ryan Thurman, Director of Sales and Marketing at Contact Center Compliance, said this can lead to artificial intelligence falsely labeling calls as spam, which prevents companies from reaching leads. By inventorying your numbers first, you can avoid wasting time on numbers that will be blocked.

Ready your equipment

If you don’t have the right equipment ready, you may not be capable of generating and transmitting attestation tokens. You can ensure your call center has the right equipment by talking to your carrier.

Contact your carriers

Your telecom carrier and some service providers are offering assistance with STIR/SHAKEN implementation. If you have questions

 or concerns, you should connect with your carrier now to get help.

Validate your calling numbers

If you operate a call center, it’s critical to work with them to validate your calling numbers with multiple carriers and their analytics partners to limit call blocking.

Signing authority

For both continued success and compliance, make sure you are using an enterprise caller that has signing authority and will give your calls an A attestation rating.

Contact the FCC

Shuster encourages businesses to urge the FCC to address and allow for a broader group of voice service providers to be able to sign calls.

“In an enterprise setting, it’s difficult to be able to validate that you have the authority to use the caller identification information that you’re using,” she said. “If those voice service providers are able to sign their own calls, then that will go a long way to eliminating that problem without the addition of technology, which is I think what they’re struggling with right now.”

CALL BLOCKING – What do I need to know?

Currently, call deliverability is at an all-time low. Carriers are using their own analytics companies, as well as data from unregulated third-party apps, to determine if a call is spam. These apps allow consumers to mark calls as robocalls, even if they are coming from legitimate businesses, such as debt collectors. These apps also come into play when calls are blocked. Agents might hear a busy signal, a disconnected tone, or may even end up talking to a robot instead of the person they tried to reach. 

How does call blocking affect me?

Though carriers will have to let callers know when their call is blocked by the deployment deadline of June 21, 2021, there is not currently a way to tell when your calls are blocked or labeled as spam. This can lead to wasted time and money spent on calls that don’t go through. It can also prevent businesses from validating these numbers to restore their legitimacy.

To avoid this problem, Shuster said, companies need to create call strategies that involve checking to make sure campaigns are going through. You should also, Thurman said, determine how to whitelist or register these numbers, preferably with a calling platform that can help you avoid future blockings.

“For Convoso, we’ve been proactively working on it,” Nima Hakimi, CEO and co-founder of Convoso. “We have certain solutions in place where calls, a certain percentage of them, are already being certified and we’re working towards that being all the way available and ready in time. So talk to your dialer providers, see what they’re doing.”

Solutions to call blocking

Call volume and calling patterns can also affect both call blocking and attestation ratings. If an illegal company spoofs your numbers, for example, the rise in call volume can lead to carriers labeling the number as spam and/or blocking its calls. This problem affects all industries and types of calls, including government numbers. To avoid losing calls, Hakimi said, businesses need to start preparing now.

Develop a strategy

Businesses should work with partners and vendors to ensure they’ll be ready by the deployment deadline. Old strategies no longer work, so you need to rethink call cadence and the lead follow-up process.

“Things are changing, as we know, and over-dialing your leads is the biggest problem,” Hakimi said. “Your contact rates will just go down. It’s a failing strategy. We really want to make sure everybody truly understands it will no longer work.”

Instead, consider assigning a specific number of caller IDs per agent or adjusting your call cadence. Keep a flexible strategy that allows you to logically adjust to changes and maintain your contact rates.

“We know that obviously in a perfect world, everybody would respond right away, but that doesn’t happen. So you need to have a system in place that can automate that lead follow-up process in a manner that doesn’t abuse the consumer and call them to death,” Hakimi said. “As long as you have systems in place that can automate that process, you won’t be in that position where you’re over-dialing and your calls get blocked.”

Implement other channels

Since you can no longer dial leads as often as before, businesses should use other channels to connect with leads. Creating an omnichannel follow-up strategy allows you to most effectively engage leads without risking your call reputation.

Validate your numbers

It’s important to make sure numbers aren’t already flagged, Hakimi said. Data providers should hold numbers until they’re clean, so work with your provider to ensure the numbers you receive won’t harm your reputation.

Though some businesses like to use services such as Numeracle or Hiya to whitelist numbers, this is often a short-term solution. Often, these numbers are blocked again in a few months and unusable. It can also be dangerous to share your information with these services, Thurman said.

Get reports from dialer platforms

Understanding what is happening with your calls is critical to avoiding blocking. Get transparent reports from providers to see if your calls are being tagged or blocked, then use this information to address the problems. You can also get recommendations from providers on the caller IDs you use and how to best manage your quantity to protect your reputation.


The best thing businesses can do today is to stay aware and proactive in your preparations, Shuster said. See what is happening with STIR/SHAKEN regulations and react accordingly to avoid problems at the deployment deadline.

“Don’t wait for these changes to happen. Talk to an attorney. Reach out to us if you have any questions,” she said. “There’s really a lot going on and the more you can educate yourself on it, the more you’ll be prepared to do something about it.”

* The materials in this presentation are provided for informational purposes only and do not constitute legal advice. Transmission of the information is not intended to create, and the receipt thereof does not constitute, an attorney-client relationship. Every situation is different, and you should not act or rely on any information contained in this presentation without first seeking the advice of an attorney.

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