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Internet Protocol Captioned Telephone Service (IP CTS) is a form of telecommunications relay service (TRS) that permits an individual who can speak but who has difficulty hearing over the telephone to use a telephone and an Internet Protocol-enabled device via the Internet to simultaneously listen to the other party and read captions of what the other party is saying. With IP CTS, the connection carrying the captions between the relay service provider and the relay service user is via the Internet, rather than the public switched telephone network. 

How IP captioned telephone service works

IP CTS is essentially a combination of two other forms of TRS: CTS and IP Relay. CTS allows a person with hearing loss but who can use his or her own voice and has some residual hearing, to speak directly to the called party and then listen, to the extent possible, to the other party and simultaneously read captions of what the other party is saying. In the most common set-up of this service, when an IP CTS user places a call over an IP CTS telephone (which is equipped with special software and a screen for displaying captions), the call is automatically connected both to the receiving party (over the PSTN) and via the Internet to a captioned telephone CA. Once connected, the CA hears and repeats or re-voices everything the other party says, and voice recognition technology automatically transcribes those words from the CA’s voice into text, which is then transmitted directly to the IP CTS user. The use of voice recognition technology allows the captions to appear on the IP CTS user’s telephone, nearly simultaneously with the other party’s spoken words. There are also versions of IP CTS that are for use with a smartphone or personal computer.

Benefits of IP captioned telephone service

IP CTS allows persons with hearing loss to take advantage of advancements in communication technologies and Internet connections at their residences and work places to more effectively use the telephone in their jobs. In addition, with some forms of the service, captions can be displayed on a screen in large text, using variable fonts and colors, thus accommodating individuals with hearing disabilities who also have low vision.

Filing a complaint

You have multiple options for filing a complaint with the FCC:

  • File a complaint online at https://consumercomplaints.fcc.gov
  • By phone: 888-CALL-FCC (888-225-5322); By videophone: 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

For more information

For more information about FCC programs that promote access to telecommunications services for people with disabilities, visit the FCC's Disability Rights Office website at fcc.gov/accessibility.

Printable Version

Internet Protocol (IP) Captioned Telephone Service (pdf)


Date Last Updated/Reviewed:

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