A caption phone is a telephone that displays written text of what the other person is saying in real time, similar to subtitles on a TV screen. It’s designed for people with hearing loss who can still use some of their remaining hearing but need to read along to follow a conversation. The service is federally funded under Title IV of the Americans with Disabilities Act, which means there is no cost to the user.
How Caption Phones Work
When someone calls you on a caption phone (or you call them), the conversation is routed through a captioning service that converts the caller’s speech into text. That text appears on a built-in screen within a few seconds of the words being spoken. You hear the caller’s voice through the handset or speaker while simultaneously reading what they’re saying. The caller on the other end doesn’t need any special equipment and may not even know captions are being generated.
The technology behind this conversion falls into two categories. The first is automated speech recognition, where AI software analyzes the audio and converts it directly into text. Multiple major providers, including CaptionCall, ClearCaptions, and Hamilton, have been certified by the FCC to offer fully automated captioning. The second method uses human captioning assistants who listen to the call and type or re-voice what the caller says. Human captioners deliver accuracy rates above 99% and are better at handling accents, industry jargon, background noise, and nonverbal context that AI can struggle with. Many services now use a hybrid approach or have shifted primarily to automated systems, though human-assisted options still exist.
What the Hardware Looks Like
Caption phones come in a few different form factors. The most common is a device that looks like a traditional desk phone with a handset, volume controls, and a large touchscreen display where the captions appear. Providers like CaptionCall, ClearCaptions, and Hamilton CapTel each manufacture their own dedicated devices.
These phones are purpose-built for hearing loss. Beyond the captioning screen, they typically include high-clarity speakers, frequency adjustments that can be tuned to match your specific hearing profile, loud visual ringers, speakerphone and voicemail functions, and compatibility with hearing aids. If you wear hearing aids with a telecoil (T-coil), caption phones produce a magnetic field that couples directly with the coil, reducing background noise and sending sound straight to your hearing aid. Under FCC standards, devices rated T3 or higher are considered hearing aid compatible. Volume controls also meet amplification requirements that benefit people with hearing loss whether or not they use hearing aids.
You don’t have to use a dedicated device, either. Several providers offer mobile and tablet apps that deliver the same captioning service on your smartphone. CaptionCall, for example, supports captions on both its hardware phones and devices running its app, so you can use the service away from home.
Who Can Get One
To use a captioned telephone service, the FCC requires you to self-certify that you have hearing loss that makes telephone captioning necessary. Some providers go a step further and ask for professional certification from a physician, audiologist, or other hearing health professional. There is no specific decibel threshold written into the rules. If you have enough hearing loss that you struggle to follow phone conversations, you generally qualify.
The service is available to veterans as well. The Department of Veterans Affairs has highlighted captioned telephone service as a free resource for veterans and their loved ones with hearing loss, following the same registration process.
Why It’s Free
Captioned telephone service falls under the FCC’s Telecommunications Relay Services program, which exists to ensure people with hearing or speech disabilities can use the phone system. Providers are compensated from a dedicated federal fund, not from the user’s phone bill or taxes in any direct way. The FCC periodically sets reimbursement rates for providers, most recently adopting a five-year compensation plan in August 2024. You pay nothing for the service itself, and many providers ship the phone hardware at no charge as well.
Privacy Protections
Because your phone calls are being processed by a third party to generate captions, privacy is a reasonable concern. FCC regulations require captioning providers to maintain the confidentiality of all personal information collected during registration and certification. Call content is treated with the same confidentiality expectations that apply to other relay services. If a human captioner is involved, they are bound by strict confidentiality rules and do not store or share the conversation after the call ends.
Caption Phones vs. Other Captioning Tools
Caption phones are specifically for telephone calls, which separates them from other captioning tools you might already know about. Your smartphone’s built-in live captioning feature (like Live Caption on Android or Live Captions on iPhone) works for media and some calls, but it uses only on-device speech recognition without the higher-accuracy systems that dedicated caption phone services provide. Video relay services, by contrast, are designed for people who use sign language and involve a sign language interpreter on a video call.
The advantage of a dedicated caption phone or app is that it’s optimized for one job: making voice calls readable. The screens are large and easy to read, the text formatting is designed for real-time conversation flow, and the audio hardware is tuned for hearing loss. For someone who makes and receives regular phone calls and finds them increasingly difficult to follow, a caption phone solves a specific, practical problem that general-purpose captioning tools handle less reliably.