The method depends on what kind of home phone service you have
Blocking a number on a home phone works differently depending on whether you use a landline through a traditional phone company, a cable provider, or a digital service like Vonage or Ooma. Some services let you block directly from your phone's handset. Others require you to call customer service or log into an online account. A few offer no blocking at all, which means you would need a separate device to filter calls before they reach your phone.
The fastest way to find out what you can do is to check your phone bill or log into your account online — your provider's website will show what blocking tools are available to you. If you are not sure who your provider is, look at the company name on your bill or the label on the box that connects to your wall jack.
Key Takeaways
- Traditional landline companies like AT&T and Verizon offer call blocking through their networks, usually activated by calling customer service or using their website.
- Cable providers like Comcast and Charter include call blocking in some plans, accessible through their online account or by calling the number on your bill.
- Digital phone services like Vonage, Ooma, and MagicJack have blocking built into their apps or web portals, where you can add numbers to a blocked list yourself.
- If your provider does not offer blocking, a separate device like a call screener box can sit between your wall jack and phone to filter unwanted calls.
- Blocking a number usually takes effect within hours, though some services process changes overnight.
Blocking through a traditional landline provider
If your home phone comes from AT&T, Verizon, CenturyLink, or a similar traditional phone company, call the customer service number on your bill and ask for call blocking. Most providers offer this at no extra cost, though some charge a small monthly fee — the representative will tell you the price before activating it.
Once activated, you can usually add numbers to your blocked list by pressing a code on your phone after a call comes in. For AT&T, this is often *60 (star-six-zero). For Verizon, it is usually *77. The exact code varies by region and provider, so ask the representative what code to use. You can also log into your account on the provider's website and add numbers there instead.
Some providers let you block entire categories — like unknown numbers, international calls, or calls from people not in your contacts. Ask the representative what options are available for your account.
Blocking through a cable provider
Comcast, Charter, Cox, and other cable companies that offer home phone service usually include call blocking as part of their phone package. Log into your account on their website (the address is on your bill) and look for a section called Phone Settings, Call Management, or Call Control. You should see an option to add numbers to a blocked list.
If you cannot find it online, call the phone support number on your bill. The representative can add numbers for you over the phone or walk you through the steps to do it yourself. Some cable providers charge a monthly fee for advanced blocking features, but basic blocking of specific numbers is usually free.
Cable phone blocking typically takes effect within a few hours. If a blocked number calls again, you will not hear the phone ring — the call will be silently rejected on the provider's network.
Blocking through a digital phone service
Vonage, Ooma, MagicJack, and similar services let you block numbers directly through their app or website. Log into your account, find the Call Blocking or Do Not Disturb section, and add the number you want to block. Most services let you add as many numbers as you want at no extra cost.
Some digital services also let you create a whitelist — a list of numbers you always want to ring through — so that only calls from those people reach your phone. Others offer a screening mode where calls from unknown numbers go to voicemail first, and you can listen before deciding whether to call back.
Check your service's app or website to see what blocking options are available. If you cannot find the feature, contact their support team through the chat or phone number in the app.
Using a separate call-blocking device if your provider does not offer blocking
If your home phone provider does not offer call blocking, or if you want more control over which calls get through, you can buy a standalone call screener. These devices sit between your wall jack and your phone and filter calls before they reach your handset. Popular options include the CPF3000 (made by Clarity), the Nomorobo device, and the Whoscall box.
Most call screeners work by comparing incoming numbers against a database of known spam and robocall numbers. When a flagged number calls, the device either blocks it silently or sends it to a special voicemail. You can usually add your own numbers to a blocked list as well.
These devices cost between $30 and $150 depending on the model and features. They require no subscription and work with any home phone service. Installation is straightforward: unplug the cord from your wall jack, plug it into the device, and plug your phone into the device.
What happens when you block a number
When you block a number, that caller will not hear a ring on their end. Instead, they will either hear a message saying the number is not in service, or the call will go straight to your voicemail (depending on your provider). They will not know they have been blocked — from their perspective, your line straightforward did not answer.
Blocked numbers can still leave voicemail if your provider allows it, though you will not be notified of the message. You can usually listen to blocked voicemails through your account online if you want to check them later.
If you change your mind and want to unblock a number, you can remove it from your blocked list through the same method you used to add it — either through your provider's website, your phone's code, or your digital service's app.
Blocking numbers that show up as "Unknown" or "No Caller ID"
Some unwanted calls come from numbers that do not display on your caller ID. If your provider offers it, you can block all calls from unknown numbers, which will prevent these calls from ringing your phone. However, this also blocks legitimate calls from hospitals, schools, and businesses that sometimes hide their numbers.
A safer approach is to use a call screener device or a digital service's screening mode, which sends unknown calls to voicemail instead of blocking them completely. This way you can listen to the message and call back if it was important.
If you want to block calls from a specific number that showed up on your caller ID, even if it displayed as "Unknown," you can usually add that number to your blocked list directly.
Frequently Asked Questions
Can I block a number if I do not know who it is?
Yes. If the number appeared on your caller ID, you can add it to your blocked list even if you do not recognize it. If the call showed up as "Unknown" or "No Caller ID," you can block all unknown calls through your provider's settings, though this will also block some legitimate calls.
Will the person I block know that I blocked them?
No. They will hear a message saying the number is not in service or the call will go to voicemail. They will not receive a notification that you blocked them.
Can I block a number on my home phone if my provider does not offer call blocking?
Yes. You can buy a standalone call-blocking device that sits between your wall jack and phone. These devices filter calls before they reach your handset and work with any home phone service.
What if a blocked number keeps calling from different numbers?
If you are being harassed by someone using multiple numbers, contact your phone provider's customer service. They can sometimes block entire ranges of numbers or flag your account for additional monitoring. You can also file a complaint with the Federal Trade Commission at reportfraud.ftc.gov.
Does blocking a number cost extra?
Most providers offer basic call blocking at no extra cost. Some charge a small monthly fee (usually $2 to $5) for advanced features like blocking entire categories of calls or creating whitelists. Ask your provider what is included in your plan.