Introduction: For many years in telecommunications, the process of two people communicating over a distance was the same for everyone. You used a device called a telephone with a receiver for listening and a microphone for speaking. Your telephone was connected to a telephone line leading to a single telephone network, as was the telephone of the person you called. Communication took place exclusively by voice, without benefit of visual information and was either inaccessible or "accessible with great difficulty" to individuals with hearing loss.
However, over the last five to ten years there has been a real paradigm shift in how people use telecommunications. Many of the new protocols, such as email, paging and instant messaging, are mainstream and popular, and afford individuals with hearing loss the benefit of visual information either as a supplement to or replacement for voice communication.
The world of telecommunications now includes voice, text, graphics and video. This innovation has happened because as technologies and media converged, new and diverse products and services have developed that are both fixed and mobile. Individuals with hearing loss now have a variety of ways to accomplish their home and business telecommuting needs -- from auditory systems like the traditional voice phone, to visual, text-based systems like 2-way pagers, to auditory plus visual systems like internet videoconferencing.
This article describes specialized and mainstream products and services currently available regarding telecommunications, as of April 2002.
Auditory Systems: The standard use of the telephone is for voice communication between two calling partners. When one or both partners have hearing loss, audibility of speech over the telephone can be problematic - whether the person is a hearing aid user or not.
Due to the 1996 amendment to the Hearing Aid Compatibility (HAC) Act of 1988, all voice telephones manufactured within or imported to the United States of America, including corded and cordless phones, must now have a volume control. Nonetheless, individuals with hearing loss may encounter or own older phones without volume controls, or they may require even more gain (loudness) than typical volume controls provide.
In these cases, a telephone amplification accessory may be useful (Holmes, 1994). These types of accessories include amplified replacement handsets and in-line amplifiers. Even assistive listening devices (e.g., Pocket Talker, several FM systems, etc) can be interfaced with the telephone using a telephone coupler to provide needed amplification. While very helpful, these devices are limited in use to modular telephones where the handset is separate from the dialing mechanism and ringer. They are not compatible with cordless telephones or phones that have the dialing mechanism in the handset. However, portable amplifiers are available that strap on to the telephone earpiece of any corded or cordless telephone.
Corded and cordless specialty phones are also available, and in many cases can provide even more amplification than add-on amplifiers. These types of phones not only provide additional amplification, but may also provide other special accessibility features (e.g., tone controls, ringer controls, audio output jacks) along with standard telephone features (e.g., memory buttons for speed dialing, built-in answering machine).
The most straightforward and common way to couple (or connect) to the standard voice telephone is acoustically - by ear, or by hearing aid. Unfortunately, acoustic coupling through a hearing aid can result in feedback and increased susceptibility to background noise. Alternatives to acoustic coupling include inductive coupling and direct audio input (Compton, 1991).
All corded and cordless phones manufactured within, or imported to the USA must be capable of coupling to a hearing aid telecoil. That is, by law, they must be "hearing aid compatible" (HAC). Importantly, induction systems such as a neckloop or silhouette inductors can provide binaural listening if the user has two telecoil-equipped hearing aids. However, these systems must be used with some type of interface to the telephone like an ALD, portable adapter or telephone coupler. Portable acoustic-to-magnetic adapters are still available. Often housed with portable amplifiers, they may provide a stronger magnetic field than what is mandated for telephone receivers. Direct audio input (DAI) from the telephone to the hearing aid is also possible using a telephone coupler, and can be used for binaural listening if the individual has two DAI-capable hearing aids. Of course, another way to achieve binaural listening is with a high quality speakerphone system!
To learn more about assistive telephone technology:
http://www.blvd.com/Hearing_Impaired_Devices/Telephones/ -- This website provides a list of manufacturers and distributors of assistive telephone technology.
http://www.tedpa.org/ -- Telecommunications Equipment Distribution Program Association (TEDPA) provides contact information by state for the distribution of specialized telecommunications equipment.
Additionally, millions of people are using cellular telephones ("cell phones") because of the convenience and safety that mobile, wireless communication provides. Some people are switching completely to wireless communications, giving up entirely their use of fixed wireline/wired telephones. Cellular telephones, like many other forms of technology, are making a technical migration from an analog implementation to a digital implementation. Unfortunately, digital wireless telephones are incompatible with many hearing aids due to the potential for radio frequency interference from the cell phone, regardless of whether acoustic or inductive hearing aid coupling is used. The interference causes an audible buzz. The buzz can be annoying and make speech understanding difficult if not impossible.
Cell phones are exempt from the legal requirements for hearing aid compatibility and volume control requirements placed on corded and cordless phones. Nonetheless, nearly all cell phones do have a volume control, and many cell phone receivers emit a magnetic field that will permit coupling to a hearing aid telecoil. For hearing aid wearers who want to use a digital wireless telephone but experience audible interference, there are a number of options.
The first option is try to locate a service provider that uses a technology called CDMA, which is less intrusive than other digital wireless technologies. If possible, the consumer should try a wireless phone of the "clamshell" style. This style has a flip-up cover with the speaker in the flip-up part of the phone and the rest of the handset electronics in the base of the phone. If this does not work, it may be necessary to use an accessory. An accessory places distance between the phone and the hearing aid, thereby reducing or eliminating electromagnetic interference. These accessories include compatible inductive neckloops, silhouette inductors and DAI-modified earbuds, each with built-in microphones for hands free phone use (Kozma-Spytek, 2001).
Visual Systems: Visual, text-based access to the telephone has traditionally been through the TTY (Slager, 1995). TTYs are terminals used for two-way text conversation over a telephone line.
Computers, through the use of special software and modems, can act like a TTY and talk to other computers with the same TTY emulation capability or standard TTYs. TTYs require turn taking on the part of the users with special etiquette for indicating the end of a turn. TTY-emulation software for computers generally has a "chat" mode, or instant messaging capabilities (more on this topic, see below) where both parties can type to each other at the same time.
To learn more about TTYs:
http://wally.rit.edu/depts/ref/research/deaf/ttyuse.html This Rochester Institute of Technology website provides TTY FAQs and general TTY etiquette tips.
http://www.tdi-online.org/ -- Telecommunications for the Deaf, Inc. (TDI) is a national advocacy organization concerned with equal access to telecommunications by individuals who are deaf or hard of hearing.
Just like wireless voice communication, wireless text communication is becoming very popular in the deaf community. There are two ways to achieve mobility for text communication. One way involves connecting a wireless telephone to a small, portable TTY. However, wireless telephones do not couple well acoustically to TTYs. They require special cable adapters as well as an audio jack on the TTY to transmit the required communication code used between TTYs. Like hearing aids, they can also experience their own type of interference when used with digital wireless cell phones such that the transmitted text becomes garbled. The FCC has ordered the wireless telephone industry to be compatible with TTY by June of this year (Harkins, 2000). Nevertheless, a wireless telephone connected to a TTY does not afford its user the same degree of portability and convenience a wireless phone user experiences.
Interactive pagers have filled this void permitting users to both send and receive text messages. These small devices have thumb keyboards and vibrating alerts, and may also handle TTY, email, and fax among other functions (Goldstein, 2000). Its important to be aware that interactive pagers cannot place calls to 911.
Probably the most familiar form of text communication over the Internet is email. As useful as email has become, it does not afford its user the ability to have real-time, two-way communication, nor does the user know if the person being sent the email is actually on-line to receive it and respond. Instant messaging (IM) is capable of both of these functions. IM users are automatically informed regarding who is on-line, and who is available for text chat. This capability is accomplished through a "buddy" list, and is referred to as "presence." IM users must be using the same (or compatible) instant messaging system to communicate with one another. Other functions, like file transfers, are incorporated into most IM software, which in many cases can be obtained from a website and used free of charge.
To learn more about instant messaging:
http://www.howstuffworks.com/instant-messaging.htm -- This website has a good article on "How Instant Messaging Works" and many other good articles on electronics and telecommunication.
The Telecommunications Relay Service (TRS) provides a protocol for a hearing person with a voice telephone and a TTY user to communicate via a regular telephone line. The call between the two parties goes through a relay operator, also called a communication assistant. The operator types to the TTY user for the voice caller and voices to the hearing person for the TTY user. TRS is mandated nationwide and provided 7 days a week, 24 hours a day, without additional cost to either caller. To reach relay services anywhere in the country, just dial 711. There are a number of different types of TRS. The type of TRS described above is called Text-to-Voice TRS. All text forms of TRS are currently carried over standard phone lines, but Internet-based TRS is being considered. MCI Worldcom has implemented a trial text-to-voice Internet relay service on their website. Individuals with hearing loss may also want to try another form of TRS, Voice Carry Over or Video Relay Services, depending on their communication preferences.
To find out more about internet-based TRS:
http://www.ip-relay.com/ -- This website is for placing text-to-voice Internet relay calls
Video relay service (VRS), a new type of relay service, was authorized by the FCC last year. Video relay service allows for sign language interpretation, rather than typing on a TTY, for relaying the speech of the hearing party. The caller uses a videoconferencing or videophone product that works with ISDN, a digital telephone service. ISDN stands for Integrated Services Digital Network and can use the same telephone wires as standard wireline service for single line use. The ISDN line is neccessary to achieve adequate video quality for sign language communication. Using an ISDN line, the VSR user contacts a video relay station where sign language interpreters are present. The interpreter places a call to the other party on a regular telephone line, and interprets the phone call in both directions. While video relay service is currently used for sign language interpreting, there is no reason why the same service could not be implemented for an oral interpreting application.
Auditory plus Visual Systems: If an individual prefers to use his own voice rather than type on a TTY, he can still use the TRS for voice carry over service. Voice carry over (VCO) allows users to read what the other person says on a TTY and talk for themselves over the telephone. The VCO user calls the relay service, and tells the relay operator he wants to make a VCO call. The operator then calls the other party. The VCO user will speak for himself, and the other person will hear the VCO users voice. When the other person speaks, the operator will type what that person says, and the VCO user will read what was said on the display window of their TTY or VCO phone.
VCO phones are combined voice phone and TTY, all in one device. They may or may not come with a standard TTY keyboard. If the VCO phone user also places TTY-to-TTY calls, she will want to have a VCO phone with a keyboard for this purpose. When using a VCO phone for VCO calls, there is no need to move the telephone handset between the TTY to receive the text and the ear to speak. Because this device is all in one, the handset can remain at the ear for the entire call. However, when the calling partner is speaking, the VCO phone user will still not be able to hear the other persons voice. In order to have that ability, another type of VCO must be used called two-line VCO. If both calling partners are using a VCO phone, then they can call one another directly without using the relay service as an intermediary as long as their phones include TTY keyboards. One manufacturer, Krown, has developed a portable VCO device that attaches over the earpiece of any voice phone enabling VCO calls through the TRS from any location.
In other TRS calls using text-to-voice or voice carry over, only one person can "speak" at a time. With Two-Line VCO (2LVCO), both parties can hear each other and talk whenever they want, permitting simultaneous, two-way voice communication and a more natural conversational experience for both parties (Wyant, 1999). This is accomplished by using two phone lines. One telephone line is for voice communication. A second telephone line is for text transmission. The voice line must have a 3-way calling feature so the relay operator can listen to the conversation and type what the hearing person says for the 2LVCO user. This means the 2LVCO user will be able to both hear and read what the other person has said. Even so, the text and speech will not occur simultaneously. The text will lag behind the speech because of the time required by the operator to type what the hearing person has said.
Although the conversation is more natural, there is more of a burden on the 2LVCO user who must maintain an additional calling feature and assume responsibility for setting up the call. It is the user who places the calls to both the TRS and the other party. The operator generally remains "invisible" to the hearing person, so its up to the 2LVCO user to ensure his calling partner speaks in a manner that allows the operator to transmit his partners speech into text comfortably. Reverse 2LVCO is also possible where the same service is used to receive incoming calls (Baquis, 1999).
To find out more about all types of TRS:
Just as many other forms of telecommunication have implementation on the Internet, videoconferencing can be accomplished through all-in-one Internet communication tools that may also include chat, whiteboard, file sharing and file transfer functions.
These software tools do require additional computer hardware to implement their voice and video components, but there is generally no cost to the software itself or the calls placed through it. Like instant messaging, both calling partners must be using the same software to communicate. In order for these videoconferencing systems to enhance communication rather than detract from it, the quality of the video and audio signals must be sufficient to approximate full-motion video and toll-quality sound.
This level of performance is unusual in current Internet videoconferencing applications due to the way in which data is sent and the rate at which it is sent over the Internet and processed by the computer running the software. Slow rates of data transfer can mean that the image being transmitted is not refreshed frequently enough to provide the detail in movement necessary for communication by sign language or by lipreading. The audio and video signals can become asynchronous. Delays can also occur between sending and receiving a message, which can lead to the calling partners "talking" over one another. Despite these problems, its not unreasonable to imagine that in the not too distant future this type of simultaneous use of multi-modal communication will work seamlessly and will be as commonplace as email and wireless phones are today.
For more information on telecommunication over the Internet:
http://www.webopedia.com/ -- This website provides an online dictionary for Internet and telecommunication terms.
http://www.webattack.com/ -- This website provides freeware and shareware downloads for accomplishing voice, text, graphic and video communication over the Internet.
The role of telecommunications in everyday life is expanding as new products and services make their way to market. Much of this technology provides individuals with hearing loss options for communication that simply werent available even ten years ago. Being aware of these options is the first step in accessing the world of telecommunications.
Baquis, C. (1999). Using two-line voice carry-over to receive incoming calls. Hearing Loss, Vol. 20(5), 10-11.
Compton, C. L. (1991). Assistive devices: doorways to independence. Annapolis, MD: Vancomp Associates.
Goldstein, L. (2000). Good vibrations: The latest in pager technology. VoltaVoices, Vol. 7(3), 20.
Harkins, J. (2000). Wireless phones: Making them work for you. Volta Voices, Vol. 7(3), 16-19.
Holmes, A. E. (1994). Telecommunications acoustic technology. In Ross, M. (Ed), Communication access for persons with hearing loss (pp.167-180). Baltimore: York Press.
Kozma-Spytek, L. (2001, February 12). Digital wireless telephones and hearing aids. Audiology Online. From http://audiologyonline.com.
Slager, R. D. (1995). Interfacing with the telephone system. In Tyler, R. S., & Schum, D. J. (Ed.), Assistive Devices for Persons with Hearing Impairment (pp. 24-65). Boston: Allyn & Bacon.
Wyant, J. (1999). Two-line voice carry-over makes direct voice telephone conversation possible for people with hearing loss. Hearing Loss,Vol. 20(5), 7-9.
The thoughtful review and helpful comments of Cynthia Compton, Ph.D., CCC-A/FAAA, Assistant Professor of Audiology/Director, Assistive Devices Center, Gallaudet University and Judith Harkins, PhD, Professor of Communication Studies/Director, Technology Access Program, Gallaudet University are greatly appreciated.