Carriers respond to Starks about robocall blocking

FCC Commissioner Geoffrey Starks released responses to his inquiries to 14 voice service providers about their plans to block suspected spam robocalls by default, on an opt-out basis. Here are highlights and excerpts from their responses.

AT&TExpanded Call Protect to opt-out basis
BandwidthDoesn’t work with end users. Concerned about improper blocking
CenturyLinkWill evaluate opt-out blocking solutions
Charter CommunicationsWill evaluate opt-out blocking solutions. Expect to provide them at no cost within 18 months.
ComcastCurrently blocking robocalls at the network level—doesn’t require opt in
Cox CommunicationsRolling out free access to Nomorobo
Frontier CommunicationsEvaluating solutions. Concerned that technology is imperfect.
GoogleDescribed free opt-in tools they provide
SprintPrefers applications rather than network blocking. Customers have to opt-in
TDS TelecomWill begin testing solutions in August, with hopes to offer a solution on opt-out basis
T-MobileHave provided network solutions for two years by default—don’t require opt-in
U.S. CellularFocusing on deploying SHAKEN/STIR and a robocall prevention service, which is opt-in
VerizonWorking on ways to provide broader call blocking at no charge as described in Commissions’ letter
VonageIntend to offer default call blocking services on an informed opt-out basis for free


AT&T is expanding AT&T Call Protect to provide automatic blocking of suspected fraud calls on an opt-out basis, at no charge, to new AT&T Mobility customers.

AT&T also is developing plans to provision call-blocking and labeling tools to even more of our customers in the coming months, also at no charge. Customers will be notified via text message when automatic fraud blocking is added to their service.


Bandwidth operates a network that is entirely optimized for Internet Protocol (“IP”) technology and predominately acts in the capacity of an underlying service provider to other innovative IP-based communications service providers.

As a result, Bandwidth is not typically positioned to offer consumer-oriented tools directly to end users itself, but is rather working to structure its underlying services in a manner that allow its customers the flexibility to deploy effective consumer-oriented solutions designed to avoid the receipt of illegal robocalls.

Bandwidth has adopted a three-pronged operational approach (prevent, detect, and mitigate) to stopping illegal robocalls in keeping with the industry efforts and best practices.

Bandwidth is concerned that without a simultaneous adoption of standards that recognize and support myriad valid reseller models, end-users that rely upon IP-enabled services that incorporate underlying PSTN functions risk having their traffic improperly blocked or discriminated against. Therefore, the importance of establishing standardized approaches for accurate call identification delivery information to network operators and recipient end-users is paramount.

The collective experience of Rural Call Completion is a recent cautionary lesson to be carefully considered as the current movement to encourage carriers to block traffic grows. Recall that the significant call delivery problems that ultimately became known as Rural Call Completion originally emanated from default call blocking treatments that were implemented as measures to help prevent pervasive abuses occurring in rural calling areas.

CenturyLink offers opt-in blocking and filtering tools and has additional opt-in service under review, for both residential and business customers.

The company is evaluating the potential for default blocking for consumers beyond its current blocking of known illegal calls, but it has not yet announced any decision about opt-out service.

CenturyLink will evaluation opt-out call blocking options based upon suitability for the customer, testing and real-world reliability and accuracy, cost, and legal and regulatory developments.

Charter Communications

Charter already offer tools that enable our customers to block anonymous calls and robocalls, and we are developing tools that will also block Do Not Originate calls.

We are also evaluating ways to deploy default call blocking with a customer opt-out capability across our residential voice network, and we anticipate that we will be able to deploy this solution without additional charge to our customers within the next 18 months.

Such a solution will leverage our anticipated deployment of SHAKEN/STIR with enhanced call analytics to enable Charter to offer a better voice service in which the customer decides what calls to accept and what services to receive.

To support our default call blocking initiative, Charter estimates that it will have implemented advanced call analytics by the second quarter of 2020.


Comcast is pleased to report that it is currently employing tools at the network level that automatically block tens of millions of illegal and fraudulent robocalls bound for Comcast’s customers, without any extra charge to customers or any need for customer opt-in.

Additionally, Comcast currently offers a range of free robocall mitigation tools that its customers may opt in to using,2 and is exploring how to make certain of these tools available on an opt-out basis, in a responsible manner that comports with the Commission’s declaratory ruling and avoids blocking desired communications wherever possible.

Comcast is developing plans in the short term to convert one of its existing opt-in blocking tools for Xfinity Voice customers—Anonymous Call Rejection—into a default, opt-out feature that remains free of charge.

Cox Communications

Cox is rolling out free access to Nomorobo. The Nomorobo service should be available to the vast majority of Cox’s residential customers throughout 2019.

Frontier Communications

Frontier continues to evaluate whether we can feasibly offer default call blocking services on an informed opt-out basis. As you are aware, technological considerations are a critical factor in our ability to stop robocalls, and the tools we offer our customers and deploy on our network depend on the network technology.

For instance, we currently offer the award-winning “Nomorobo” service for custoemrs who subscribe to VoIP service (Nomorobo is incompatible with TDM).

Frontier is still evaluating whether to provide these consumer tools on an opt-out basis given that the technology is far from perfect.

Consequently, Frontier is concerned about blocking legitimate calls without customers affirmatively accepting that risk by opting in to the service.

Frontier will continue to evaluate whether opt-out call blocking is the right path for its customers as existing technologies evolve and new technologies develop.


(Google’s response describes the free software tools they offer on an opt-in basis.)


Sprint has partnered with TNS and its Cequint mobile client subsidiary to develop an application for Sprint wireless customers that provides a robocall labeling and blocking service called Premium Caller ID, which labels incoming robocalls and allows customers to selectively block calls based on risk level.

Sprint will offer a free version of this call blocking application in the near future for both postpaid and prepaid customers and will promote this service widely to its customers with electronic messaging, website content, and default installation on new devices where feasible.

Sprint is investigating how best to implement an “opt-out” strategy given Sprint’s current application-based approach to blocking illegal robocalls. Sprint expects application-based call blocking to be more accurate and provide customers greater flexibility and control than network-based approaches.

Because some device manufacturers do not permit pre-installation of carrier custom software, however, some customer action may be required to activate and configure even a free anti-robocall application. Sprint continues to investigate additional tools, including network-based solutions, which may provide further protections without proactive customer action.

Sprint remains concerned that the lack of a safe harbor for accidental or erroneous call blocking could result in significant liability exposure for carriers. The proposed safe harbor for SHAKEN/STIR authentication does not address this issue because SHAKEN/STIR data will likely be only one factor of many in deciding whether a given call is illegal or unwanted. Because it is inevitable that legal calls will occasionally be falsely identified as illegal robocalls, carriers must have some form of liability protection in those circumstances.

TDS Telecom

TDS Telecom has been exploring currently available call identification and blocking solutions that it could potentially deploy in its TDM and IP networks to protect our subscribers from unlawful robocalls.

TDS Telecom expects that it will bring an analytics-based blocking solution into a test environment in both our TDM and IP networks in August.

We are optimistic that testing will confirm the analytics solution as a meaningful tool in the fight against unlawful robocalls, including as an opt-out service.


More than two years ago, we introduced Scam ID and Scam Block, network-based tools available to all postpaid T-Mobile customers and Metro by T-Mobile customers.

Scam ID and Scam Block work automatically on all iOS and Android devices.

Because these tools are network-based, customers do not need to do anything to turn them on—there are no apps to download or handset settings to change to access these services.

U.S. Cellular

Currently our primary focus is on the implementation of SHAKEN/STIR technology within our network.

We are cautiously optimistic that, provided SHAKEN/STIR is implemented by the major carriers, we will see a profound reduction in the number of illegal robocalls. In the meantime, there are a number of useful apps that customers can use to take proactive steps to reduce the number of robocalls they receive.

The Call Guardian app is now controlled by TNS, one of the vendors we have selected to implement SHAKEN/STIR, by virtue of its acquisition of Cequint. We believe that these two solutions, SHAKEN/STIR and the Call Guardian, operating in concert will have a substantial impact on the total number of illegal robocalls customers receive.

Call Guardian is not a default service as described in the Commission’s June 6th order since it needs to be activated by customers who then can choose between a number of options that best suits their individual needs for handling the calls that they receive.


We recently incorporated into our “Call Filter” service the results of the caller ID verification that we can do for calls enabled with the STIR/SHAKEN authentication technology. That allows us to make better decisions about whether to block or label a call as spam.

We are actively working on ways to take advantage of the Commission’s most recent order to more broadly make call blocking available to our customers. I can confirm that we have no intention of starting to charge customers for blocking.

And as Verizon continues to expand and improve our customers’ blocking experiences, we will ensure customers are informed about what opt-in or opt-out blocking we do on their behalf so that they are empowered to modify or remove the blocking service.


We intend to offer default call blocking services on an informed opt-out basis.

We are actively engaging with vendors and other industry partners to make these blocking tools available as quickly as possible, and those discussions will influence our timeline for implementation.

We intend to communicate blocking options to our customers through our website, our customer portal, e-mail, and/or communications from account managers.

Our current expectation is that Vonage will absorb these costs for residential customers.

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We provide comprehensive robocall prevention and STIR/SHAKEN capabilities in our ClearIP and NexOSS software platforms. Contact us today to see how our solutions can quickly enable you to provide the solutions described by the FCC and sought by consumers and enterprises.

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