How Captioned Telephone Services Work and Who Can Use Them

What captioned telephone services do

Captioned telephone is a phone service that displays a real-time written transcript of what the other person says, word for word, on your phone screen. A trained operator listens to the call and types what they hear so you can read it as the conversation happens. You speak normally into the phone — the other person hears your voice directly, not a recording — and you read their responses instead of listening to them.

This is different from relay services that require the other person to know they're on a relay call. With captioned telephone, the person calling you has no idea an operator is involved. They experience a normal phone call on their end.

The service is free through the federal Lifeline program if you meet income requirements. You can use it on a regular landline, a cell phone, or a computer with internet. The captions appear on a device you control — usually your phone's screen or a separate caption display box.

Key Takeaways

• Captioned telephone shows you a written transcript of the other person's words in real time, while they hear your voice normally.
• The service is free through Lifeline if your household income is at or below 135 percent of the federal poverty line, with no asset limits.
• You need to register with a captioning provider and choose how you want to receive captions — on your phone, a tablet, or a separate display device.
• Caption accuracy depends on the operator's speed and the call quality, and typically runs 80 to 95 percent accurate.
• You can use captioned telephone for any call — personal, business, medical appointments — and the other person will not know captions are being provided.

How the captioning actually happens during a call

When you make or receive a call through a captioning provider, a live operator in a call center listens and types simultaneously. The words appear on your screen with a slight delay — usually one to three seconds behind what the person is actually saying. This lag is short enough that you can follow a natural conversation, though you may occasionally miss a word or need the person to repeat something.

The operator is trained to type conversational speech, including filler words and tone cues like "um" or "[laughs]" so you get the full sense of what's happening. They do not edit or clean up the speech. If someone mumbles or speaks unclearly, the operator types what they heard, and you see that uncertainty in brackets like "[inaudible]" or "[unclear]."

The call quality and the operator's typing speed both affect accuracy. A quiet call with clear speech will produce captions closer to 95 percent accurate. A noisy call or rapid speech might drop to 80 percent. If you miss something, you can ask the other person to repeat, just as you would on any phone call.

Who pays for it and how to register

Captioned telephone is funded by the federal Lifeline program through the Universal Service Fund. There is no cost to you if you meet the income requirement: your household income must be at or below 135 percent of the federal poverty line. The poverty line changes each year, so the income limit varies. For 2024, that means a single person earning roughly $18,000 per year or less, though the exact number depends on your state and household size.

To register, you contact a captioning provider directly. The major providers are Sorenson Communications, CaptionCall, Innocaption, and Hamilton Relay. Each one has a website and a phone number where you can sign up. You will need to provide proof of your income — usually a recent tax return, a pay stub, or a benefit letter from Social Security or another program. You may also need to show proof of identity and your current phone number.

Once you are registered, the provider sends you a device or gives you instructions to download an app, depending on which method you choose. Some providers send a physical caption display box that sits next to your phone. Others let you see captions on your smartphone screen or tablet. A few offer both options so you can switch depending on where you are.

Different ways to receive captions

Captioning providers offer several ways to see the captions, and you can usually switch between them or use more than one at the same time.

Caption display box: A small device that connects to your landline phone. Captions appear on a built-in screen. This is the most common setup for people who use a home phone. The box costs nothing if you may have access to for Lifeline.

Smartphone or tablet app: You download an app from the provider, and captions appear on your phone or tablet screen during calls. This works on both iPhone and Android. You can use it on your regular cell phone number.

Computer or laptop: Some providers let you make calls through their website or software, and captions display on your computer screen. This is useful if you spend a lot of time at a desk.

Video relay service: A few providers offer captioned video calls where you see the other person and captions at the same time. This is less common and may have different availability depending on your provider.

Ask your provider which options they support in your state. Availability varies, and some states have more options than others.

What captioned telephone works well for

Captioned telephone is designed for any conversation you need to have by phone. People use it for doctor's appointments, customer service calls, family conversations, work calls, and emergency situations. Because the other person hears your voice normally, they do not need any special equipment or knowledge. You can call anyone — a business, a government office, a friend — and they will not know you are using captions.

The service works best for one-on-one calls. If multiple people are talking in the background on the other end, the operator types what they can hear most clearly, which may not capture everyone. Similarly, if you are in a very noisy environment, the operator may struggle to hear you clearly, and you may need to move to a quieter spot or ask the other person to speak up.

Captioned telephone is not designed for video calls, group conference calls, or calls where you need to hear music or audio quality (like listening to hold music). For those situations, other relay services or accessibility features on your phone may work better.

Accuracy, delays, and what to expect

Captions are not perfect. Operators are human and type as fast as they can, but they cannot capture every word in real time, especially if someone speaks quickly or with an accent. You will see occasional gaps, misspellings, or words that do not quite match what was said. Most of the time these are close enough that you understand the meaning. Sometimes you will need to ask the other person to repeat or spell something out.

The delay between speech and captions is usually one to three seconds. This is short enough that conversation flows naturally, but you will notice you are reading slightly behind what is happening. Some people find this easy to adjust to within a few calls. Others take longer to get used to it.

Caption quality also depends on call quality. A clear landline call with good audio produces better captions than a cell phone call with background noise. If you are having trouble understanding the captions, try moving to a quieter location or asking the other person to speak more slowly.

How captioned telephone differs from other relay services

Captioned telephone is one of several relay services available through Lifeline. The main difference is that with traditional relay services, the other person knows they are on a relay call and has to wait for an operator to relay messages back and forth. With captioned telephone, the other person experiences a normal phone call.

Video relay service is another option if you use sign language. With video relay, you connect with a sign language interpreter on video, and the interpreter relays your conversation to the other person by voice. This works well if sign language is your primary communication method.

Speech-to-speech relay is available if you have a speech disability. An operator listens to your speech and relays what you say to the other person in clear, understandable speech. The other person hears the operator's voice, not yours.

Captioned telephone is the right choice if you are deaf or hard of hearing and prefer to speak for yourself while reading the other person's words. It gives you the most control over how you communicate and the most privacy, since the other person does not know an operator is involved.

Frequently Asked Questions

Can I use captioned telephone on my cell phone?

Yes. Most providers offer a smartphone app that works on your regular cell phone number. You download the app, and captions appear on your phone screen during calls. Some providers also let you use a caption display box with a cell phone if you prefer that setup.

What if the captions are wrong or I miss something?

You can ask the other person to repeat or spell out what they said, just as you would on any phone call. There is no penalty for asking for clarification. If you consistently have trouble with a particular provider's accuracy, you can switch to a different captioning provider.

Do I have to tell the other person I am using captioned telephone?

No. The other person hears your voice directly and experiences a normal phone call. You do not have to disclose that you are using captions. Some people choose to tell the person they are calling for personal reasons, but it is entirely your choice.

What if my income changes or goes above the limit?

You should report the change to your captioning provider. If your income exceeds the limit, you will no longer be covered by Lifeline. Some providers offer paid captioned telephone services if you want to continue, but you would pay out of pocket.

Can I use captioned telephone for 911 calls?

Captioned telephone is not designed for emergency calls. If you need to call 911, use your regular phone or text-to-911 if your area supports it. Check with your local emergency services to see what options are available in your location.