ADAAG Manual

Text Telephones (or TTYs) [4.31.9]

What is a text telephone? ... a TTY? ... a TDD? These are different names for the same thing: it is a device that allows people with hearing or speech impairments to communicate over the telephone. Like computers with modems, TTYs provide some form of keyboard input and visual display output. Devices typically include an acoustic coupler for the telephone handset, a simplified keyboard, and a visible message display. Typed messages are converted into audible tones transmitted through the phone line to a receiving unit. Early models were known as TTYs (from their origin in teletype technology). Smaller, more portable versions developed later were called TDDs (telecommunications devices for deaf persons), a term still used on the signage symbol used to identify them. ADAAG refers to these devices as text telephones but the abbreviation "TTY" is preferred by most TTY users.

Using TTYs

Many TTYs are connected to phones by placing the handset in an acoustic coupler although a number of models connect directly to a standard analog phone line. On a TTY call, both parties must have a TTY. (Title IV of the ADA establishes a 24-hour relay service so that calls can be made through an intermediary when only one party has a TTY). Short words and sentences save time and many abbreviations and contractions are used. Certain conventions are standard, such as typing "GA" (go ahead) after each message; this tells the other person on the line to begin typing a response.

Recognizing a TTY Call

Where TTYs share a voice line, it is important that persons answering the phone know how to recognize a TTY call. A series of beeping tones is the most common signal (made when the person calling taps the keyboard space bar) but not all models emit this sound. Some models are equipped with voice announcers. Since there may not always be an audible cue by the caller, check to see if it is a TTY call when nothing is heard. (When a call is made through the TTY relay service, the service operator will indicate by voice that it is a TTY relay call.)

How TTYs Work: Transmission Codes

TTYs generate and receive text through tones similar to those of touch-tone phones. There are two standard codes for transmitting text: Baudot and ASCII. This is an important consideration when buying or specifying a TTY. TTY technology was standardized on Baudot (5-bit) codes in the 1960s while computer applications require an ACSXI (8- bit) format. Baudot code has fewer characters and a slower transmission rate but will likely remain the standard for TTYs in the years ahead as ASCII dominates the market. ASCII, while faster than Baudot, provides more capability than necessary for TTYs and is susceptible to interruptions such as call waiting, transfers, and line noise. For this reason, telephone emergency services, such as 911 and similar fast-dial lines, must be compatible with Baudot. Many TTYs have an ASCII option. Also available are TTYs with Turbo Code, an enhanced Baudot code with a faster transmission speed employed automatically when used with other TTYs with this capability.

Public Pay Phones

As a design guideline, ADAAG primarily covers only fixed building elements. This is why it addresses TTY access only at public pay phones. Some pay phones that are card-operated incorporate TTY technology. Although ADAAG requirements apply only to fixed telephones, other requirements in the ADA require communication access. For example, the Department of Justice title III regulation requires public accommodations to provide TTYs on request when customers, clients, patients or participants are permitted to make outgoing calls on more than an incidental convenience basis.

Permanently Fixed vs. Portable TTYs

While TTYs are available in a variety of designs, including portable models, ADAAG requires TTYs to be permanently fixed at pay phones. This allows ready and independent access for people needing them. Portable TTYs provided on an as-needed basis cannot substitute for fixed devices except in certain limited situations as an "equivalent facilitation" where they can be made readily available (i.e., nearby pay phones) at all times that the public pay phones can be used. ADAAG gives the example of a hotel registration desk in the vicinity of pay phones staffed at all times. Portable devices can be used to provide access to desktop and residential-type phones under ADA requirements outside ADAAG. This includes access to phones in hospital and hotel rooms; (TTYs at hospital or hotel front desks will allow patients or guests using TTYs in their rooms to access in-house services).

In new construction, TTY equipment can be provided as part of the pay phone contract with a phone company, independent pay phone provider, or route subcontractor. For existing installations, contact the phone service provider to add a TTY to an existing bank or to modify an existing pay phone enclosure with a shelf and power outlet to accommodate a portable device. Adding a shelf or power outlet or, where vandalism is not a concern, attaching a portable TTY next to an existing phone can also be done by a carpenter or construction contractor.

TTY Scoping [4.1.3(17)(c)]

ADAAG requires at least one TTY on site when there are four or more pay phones (and at least one is interior) and in specific buildings or locations when a pay phone is provided. In many cases, only one TTY-equipped pay phone is required on a site. Recommendations: From a practical standpoint, it would be considered good design to place additional units at some multi-facility sites or large buildings. For example, consider that a "site," as defined in ADAAG, can apply to an entire college campus, office complex, or shopping plaza. At sites with many buildings or long distances between phone banks, it is a good idea to provide TTYs at more than one location and, in some cases, at several locations. One should also consider a facility's use. ADAAG recognizes the importance of public access to phones in hospitals, airports, and transit stations but TTYs also may be advisable in other occupancies where public use of phones is equally important.

Alterations

In general, ADAAG requires a text telephone where four or more pay phones are added or altered. This includes replacement of existing pay phones with units of different types, relocating existing pay phones, or installing new pay phones where none had previously been located. (Lowering existing pay phones for wheelchair access or replacing a non-functioning unit with one of the same type are not considered "alterations" that trigger the requirement for text telephones, although phone replacement may offer cost-effective opportunities to provide such access).

Location and Signage

ADAAG does not specify where text telephones are to be located on a site or in a building (except in hospitals, airports, and transit stations). It is best to locate them along primary circulation routes and in central or prominent phone locations so they are easy to find. Since not all phones or banks are equipped with TTYs, signage is important. Signs are required at all phone banks without TTYs indicating the location of the nearest TTY; (if there are no other banks, directional signage is required at building entrances. Additional signage, such as on building maps, is helpful too. Signs labeling pay phones with TTYs is required as well, in part because integrated TTYs may not be easily identified. An international symbol as specified in 4.30.7 is used on all TTY signs. ADAAG does not specify sign size, or in the case directional signs, verbal content, but requires a light-on-dark or dark-on-light color contrast between the content and the background and a non-glare finish.

Shelf and Outlet

Some people travel with their own portable TTY units. ADAAG includes provisions for portable units shelves and power outlets at all banks with 3 or more pay phones. (Those who travel with laptop computers will also find these provisions useful). The shelf must provide a vertical clearance of at least 6 inches so that different types of portable TTY devices can be connected. Recommendations: A shelf at least 10 inches square will accommodate most models. Phones should have a standard handset so that they fit the typical TTY coupler. The power outlet must be in or adjacent to the telephone enclosure (typical TTY cord is about 3 feet long).

TTY Access at Wheelchair Accessible Phones

ADAAG includes specifications for wheelchair access to public phones. It is possible for a single unit to serve both people who use wheelchairs and those who use text telephones with careful design and placement of a standard TTY adjacent to an accessible pay telephone. However, if located below accessible units, the device may be too low for standing persons to use the keyboard comfortably or to see the display screen. They may also obstruct front approach knee space below phones for people using wheelchairs.

Selecting a TTY

Under ADAAG, TTYs can be permanently fixed within or next to phone enclosures. Pay phones with integrated TTYs are available. One model provides a vandal-proof metal drawer for attachment beneath a pay phone housing. The drawer containing the keyboard and screen automatically opens for use only when the call is answered by another TTY. Another model provides a coupler, screen, and keyboard within an enclosure than can be installed next to a wall-mounted pay phone. Portable devices can also be permanently secured within or next to telephone enclosures. Vandal-resistant and weather proof TTYs are available for outdoor use, including at exterior-only sites such as highway rest areas and parks. (Since outdoor models were not available when ADAAG was first published, it does not currently address exterior installations but will likely do so in future updates.)

Recommendation: When buying or specifying a TTY to satisfy ADAAG or other ADA requirements, it is helpful to consider:

• Power Supply TTYs integrated with pay phones are permanently wired to the power system. Most portable devices require a standard 110 volt receptacle near the phone.

• Display Most TTYs use either a back lit LCD display or an LED display. The number of characters in the display at one time may vary from 1 line (20 characters) to 2 lines (80 characters). Since it can be difficult to write down information as it is read, the 2-line display can be helpful.

• Connection to Phones and Phone Lines When selecting a TTY with acoustic couplers, consider the design of telephone handsets. Most couplers are designed to fit standard rounded handsets like those usually found on pay phones. TTYs that connect directly to phone lines do not require coupling through the telephone handset. Where phone systems are digital, a special connector (digital-analog converter) is needed and can be obtained from a phone provider.