Call Blocking Tools and Resources

Call blocking is a tool used by phone companies to stop illegal and unwanted calls from reaching your phone. A recent FCC report found that by partnering with third-party analytics companies, providers are able to block billions of unwanted calls to American consumers each year.

Phone companies sometimes block calls connected to suspicious calling patterns proactively for their customers. Many phone companies also enable their customers to block additional unwanted calls by enrolling in a service or installing an app. Consumers can also adjust certain settings on their phone, sign up with a third-party service, or download a third-party app to block suspected unwanted calls.

Depending on your service provider, a blocked call may go straight to your voicemail, you may hear a single ring and get caller ID information from the blocked call, or you may get no notice at all.

Many phone companies are taking advantage of FCC rules that allow consumers to be enrolled automatically in call blocking services, but you can opt-out if you are concerned about missing wanted calls. A number of companies also offer call labeling to help consumers determine which calls they want to answer. Labeling services display categories for potentially unwanted or illegal calls such as “spam” or “scam likely” on the caller ID display.

Call Blocking and Labeling Resources
Contact your phone company to learn more about the blocking and labeling solutions that may be available to protect you from unwanted and illegal calls. There may also be apps you can download for your mobile device – at little or no cost – to block or label potential spam calls. In addition to call blocking and labeling services, you should also check with your wireless device manufacturer about built-in features you can use to block unwanted calls from specific numbers using your cell phone’s settings.

The resources listed below* provide information on many of the call blocking and labeling tools currently available to consumers.

AT&T: Mobile security and call protection services.
Google Project Fi: Call blocking options for Project Fi wireless service.
Sprint: Call blocking options using My Sprint.
T-Mobile: Call-protection options to identify or block potential scammers.
U.S. Cellular: Automatic network call identification, labeling, and blocking app options.
Verizon: Call Filter FAQS for screening and blocking unwanted calls.

AT&T: Information on Digital Phone Call Protect service, call blocking, and other features.
CenturyLink: Customer tips and tools to block unwanted calls.
Comcast: Call blocking options for XFINITY Voice subscribers.
Frontier Communications: Consumer options for call blocking tools and services.
Spectrum: Guide for using Nomorobo service to block robocallers.
Verizon: Customer options for stopping unwanted calls to residential lines.

Third-Party Analytics Resources
First Orion: Tools and services for mobile customers and businesses.
Hiya: Tools and services for mobile phones; Hiya Connect for businesses.
Nomorobo: Tools and services for VoIP landlines and mobile phones.
TNS Call Guardian: Call analytics solutions for businesses.
YouMail: Tools and services for individuals and businesses.

Wireless Device Solutions
Apple iPhones have an opt-in “Silence Unknown Callers” call-screening and blocking feature.
Google Pixel phones have a “Call Screen” call-screening and blocking feature; Google offers several free, opt-in, call-blocking tool apps for Android phones; and Google Voice users can use a call management tool to block unwanted calls.
Samsung partners with Hiya to offer a call-blocking solution called Smart Call to label potentially unwanted calls.

Trade Association Consumer Resources and Information
CTIA: Consumer resources for stopping robocalls.
US Telecom: Consumer information on illegal robocalls.

*The resources listed are provided for informational purposes. The FCC does not endorse any products or services listed, and is not responsible for the content, accuracy, completeness, or timeliness of non-FCC websites.

How Businesses Can Avoid Having Legitimate Calls Blocked
Phone companies, or their partner service providers, look for suspicious calling patterns in their ongoing efforts to proactively block unwanted and illegal calls. False-positive blocking may occur if a legitimate business or other entity places calls using a pattern similar to those associated with unwanted – and often illegal – robocalls.

Here are some best practices to avoid being blocked:
• Always use a valid outgoing number.
• Never display an invalid number in caller ID.
• Never substitute a phone number in caller ID to which you do not subscribe.
• Do not use an outgoing number that is on the Do Not Originate list.
• Limit the number of calls placed per minute, particularly outside of normal business hours.
• Limit the number of times you call numbers back within a short time frame.

You should also periodically check with phone companies and third-party analytics companies about consumer complaints for the numbers you use to place calls.

When leaving messages include a consistent call-back number and consider including additional contact information that recipients can use to report concerns.

You can also use different outbound numbers for different purposes. For example, customer support call-backs are less likely to be blocked based on complaints if they are made using a distinct number and not one shared with outbound telemarketing calls, which may draw complaints.

In addition, be sure to register the valid numbers you plan to use for outgoing calls with the entities listed below, not just the phone company that provides your service.
AT&T: Call 800-337-5373, email, or contact Hiya through its website, Calling parties can also provide feedback at, which links to Hiya’s portal.
CenturyLink: Email, or contact Nomorobo at and choose “Report a Number.”
First Orion: Contact via website at
Frontier: Email, or contact Nomorobo
Hiya: Contact through website at Hiya provides a service for legitimate businesses to register, through
Nomorobo: Contact through website at and choose “Report a Number.” Nomorobo has a white list feature to which subscribers can add numbers in order to prevent erroneous blocking.
Sprint: Call 888-211-4727 or contact TNS at
T-Mobile: Contact through or through First Orion at
TNS: TNS provides a portal on its website for identifying inaccuracies, through its robocall feedback website,, and it allows companies to subscribe to alerts to inform them when the number is classified as a spammer, spoofer, scammer, or robocaller.
US Cellular: Call 888-944-9400 or contact through website at
Verizon: Contact through website at
Windstream: Call 800-347-1991 or contact by email at website:

Some of the above companies also offer call labeling to help consumers decide which calls they want to answer. These companies may be able to address any questions you have regarding how your calls are being labeled.

Know the rules
First and foremost, make sure you have the consent of the person you are calling before you call. FCC rules require a caller to obtain written consent – on paper or by electronic means such as a website form or a telephone keypress – before making a prerecorded telemarketing call to a landline phone number or before making an autodialed or prerecorded telemarketing call to a wireless phone number. FCC rules also require callers to obtain oral or written consent before making autodialed or prerecorded non-telemarketing calls or texts to wireless numbers. There are exceptions to these rules, such as for emergencies involving danger to life or safety.

Under FCC rules, telemarketers calling your home must provide their name along with the name, telephone number, and address where their employer or contractor can be contacted. Telephone solicitation calls are prohibited before 8 am and after 9 pm.

Telemarketers are no longer able to make telemarketing robocalls to wireline home telephones based solely on an “established business relationship,” which may have been established when the consumer purchased something or contacted the business to ask questions. Prior express consent as described above is necessary, even if a telemarketer has an established business relationship with the called party.

Make sure you comply with the Do Not Call provisions of the Telemarketing Sales Rule. (See the Federal Trade Commission’s Do Not Call Q&A for more information.)

Learn more about unwanted calls and texts, including additional information on FCC rules for autodialed calls, at

Understand what the FCC authorizes
Under FCC rules, voice service providers may block the following calls without consumer consent:
• Calls from unassigned, unallocated, or invalid numbers.
• Calls from numbers on the Do Not Originate list.
A voice service provider may also block calls that it deems are unwanted based on reasonable analytics, but the provider must allow their customers to opt out of this type of blocking.

Filing a complaint
You have multiple options for filing a complaint with the FCC:
• File a complaint online at
• By phone: 1-888-CALL-FCC (1-888-225-5322); TTY: 1-888-TELL-FCC (1-888-835-5322); ASL: 1-844-432-2275
• By mail (please include your name, address, contact information and as much detail about your complaint as possible):

Federal Communications Commission
Consumer and Governmental Affairs Bureau
Consumer Inquiries and Complaints Division
45 L Street NE
Washington, DC 20554

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Last Reviewed: 11/10/20


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