Telecommunications Relay Service (TRS) allows persons with who are deaf, hard of hearing, deaf-blind or who have speech disabilities to place and receive telephone calls. A communications assistant (CA) relays the call back and forth between the person with a disability and the other party to the call. For example, in text-to-voice TRS, a person with hearing loss communicates in text what s/he wishes to communicate to the other party and the CA repeats in voice what the user has typed, and types back to the TRS user what the voice telephone user responds.

There are several forms of TRS that consumers can use, depending on the nature of the disability and whether they have some hearing or can speak. These include traditional TRS, which uses a text telephone or TTY device and a telephone line, Speech-to-Speech (STS), which uses specially trained CAs who can relay difficult-to-understand speech, and Captioned Telephone Service (CTS), which is described below in this consumer guide. CTS is available both over the regular telephone network (the “public switched telephone network) and over the Internet. Two other forms of TRS that use the Internet are Internet Protocol (IP) Relay, in which a person with a disability sends text over the Internet and receives messages back (through the CA) in voice, and Video Relay Service (VRS), in which the person with a disability uses American Sign Language to communicate with a third party through an interpreter who knows sign language. For a more detailed description of the various forms of TRS, see the FCC’s TRS consumer guide.

The Federal Communications Commission has ruled that IP Captioned Telephone Service (IP CTS) calls are an approved form of TRS that may be compensated from the Interstate TRS Fund. Like all TRS calls, the relay costs associated with IP CTS are not paid directly by users of the service.

The FCC recently established temporary requirements for IP CTS to ensure that the program is provided efficiently to persons with hearing loss who need to use the service. (See Temporary Requirements Section below.)

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 users places a call over a 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 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.

Emergency call handling procedures

The FCC has adopted procedures for IP captioned telephone services (CTS) that require the provider, at minimum, to automatically and immediately transfer an emergency call to the appropriate 911 call center or ensure that appropriate personnel are notified of the emergency.

IP CTS providers must also: 1) prioritize emergency calls over nonemergency calls; 2) communicate to the emergency personnel answering the call the name of the TRS user, the location of the emergency, the name of the provider, the CA’s call-back number, and the CA’s identification number; and 3) re-establish contact between the caller and emergency personnel if the call is disconnected.

Print out

Internet Protocol (IP) Captioned Telephone Service Guide (pdf)


Date Last Updated/Reviewed: 
Friday, September 8, 2017