|Measurement Range||Minimum in Inches |
Maximum in Inches
|1. Measured center to center.|
|Dot base diameter||0.059 (1.5 mm) to |
0.063 (1.6 mm)
|Distance between |
two dots in the same cell 1
|0.090 (2.3 mm) to |
0.100 (2.5 mm)
|Distance between |
in adjacent cells 1
|0.241 (6.1 mm) to |
0.300 (7.6 mm)
|Dot height||0.025 (0.6 mm) to |
0.037 (0.9 mm)
|Distance between |
from one cell directly below 1
|0.395 (10 mm) to |
0.400 (10.2 mm)
Advisory 703.5.1 Finish and Contrast. Signs are more legible for persons with low vision when characters contrast as much as possible with their background. Additional factors affecting the ease with which the text can be distinguished from its background include shadows cast by lighting sources, surface glare, and the uniformity of the text and its background colors and textures.
|Height to Finish Floor or Ground |
from Baseline of Character
|Horizontal Viewing Distance||Minimum Character Height|
|40 inches (1015 mm) |
to less than or equal to 70 inches (1780 mm)
|less than 72 inches (1830 mm)||5/8 inch (16 mm)|
|72 inches (1830 mm) and greater||5/8 inch (16 mm), plus 1/8 inch (3.2 mm) per foot (305 mm) |
of viewing distance above 72 inches (1830 mm)
|Greater than 70 inches (1780 mm) |
to less than or equal to 120 inches (3050 mm)
|less than 180 inches (4570 mm)||2 inches (51 mm)|
|180 inches (4570 mm) and greater||2 inches (51 mm), plus 1/8 inch (3.2 mm) per foot (305 mm) |
of viewing distance above 180 inches (4570 mm)
|greater than 120 inches (3050 mm)||less than 21 feet (6400 mm)||3 inches (75 mm)|
|21 feet (6400 mm) and greater||3 inches (75 mm), plus 1/8 inch (3.2 mm) per foot (305 mm) |
of viewing distance above 21 feet (6400 mm)
Advisory 703.6.2 Finish and Contrast. Signs are more legible for persons with low vision when characters contrast as much as possible with their background. Additional factors affecting the ease with which the text can be distinguished from its background include shadows cast by lighting sources, surface glare, and the uniformity of the text and background colors and textures.
Advisory 703.7.1 Finish and Contrast. Signs are more legible for persons with low vision when characters contrast as much as possible with their background. Additional factors affecting the ease with which the text can be distinguished from its background include shadows cast by lighting sources, surface glare, and the uniformity of the text and background colors and textures.
Advisory 704.2.1 Clear Floor or Ground Space. Because clear floor and ground space is required to be unobstructed, telephones, enclosures and related telephone book storage cannot encroach on the required clear floor or ground space and must comply with the provisions for protruding objects. (See Section 307).
Advisory 704.3 Volume Control Telephones. Amplifiers on pay phones are located in the base or the handset or are built into the telephone. Most are operated by pressing a button or key. If the microphone in the handset is not being used, a mute button that temporarily turns off the microphone can also reduce the amount of background noise which the person hears in the earpiece. If a volume adjustment is provided that allows the user to set the level anywhere from the base volume to the upper requirement of 20 dB, there is no need to specify a lower limit. If a stepped volume control is provided, one of the intermediate levels must provide 12 dB of gain. Consider compatibility issues when matching an amplified handset with a phone or phone system. Amplified handsets that can be switched with pay telephone handsets are available. Portable and in-line amplifiers can be used with some phones but are not practical at most public phones covered by these requirements.
Advisory 704.4 TTYs. Ensure that sufficient electrical service is available where TTYs are to be installed.
Advisory 704.4.1 Height. A telephone with a TTY installed underneath cannot also be a wheelchair accessible telephone because the required 34 inches (865 mm) minimum keypad height can cause the highest operable part of the telephone, usually the coin slot, to exceed the maximum permitted side and forward reach ranges. (See Section 308).
Advisory 704.4.1 Height Exception. While seats are not required at TTYs, reading and typing at a TTY is more suited to sitting than standing. Facilities that often provide seats at TTY’s include, but are not limited to, airports and other passenger terminals or stations, courts, art galleries, and convention centers.
Advisory 706.1 General. Assistive listening systems are generally categorized by their mode of transmission. There are hard-wired systems and three types of wireless systems: induction loop, infrared, and FM radio transmission. Each has different advantages and disadvantages that can help determine which system is best for a given application. For example, an FM system may be better than an infrared system in some open-air assemblies since infrared signals are less effective in sunlight. On the other hand, an infrared system is typically a better choice than an FM system where confidential transmission is important because it will be contained within a given space.
The technical standards for assistive listening systems describe minimum performance levels for volume, interference, and distortion. Sound pressure levels (SPL), expressed in decibels, measure output sound volume. Signal-to-noise ratio (SNR or S/N), also expressed in decibels, represents the relationship between the loudness of a desired sound (the signal) and the background noise in a space or piece of equipment. The higher the SNR, the more intelligible the signal. The peak clipping level limits the distortion in signal output produced when high-volume sound waves are manipulated to serve assistive listening devices.
Selecting or specifying an effective assistive listening system for a large or complex venue requires assistance from a professional sound engineer. The Access Board has published technical assistance on assistive listening devices and systems.
Advisory 706.3 Receiver Hearing-Aid Compatibility. Neckloops and headsets that can be worn as neckloops are compatible with hearing aids. Receivers that are not compatible include earbuds, which may require removal of hearing aids, earphones, and headsets that must be worn over the ear, which can create disruptive interference in the transmission and can be uncomfortable for people wearing hearing aids.
Advisory 707 Automatic Teller Machines and Fare Machines. Interactive transaction machines (ITMs), other than ATMs, are not covered by Section 707. However, for entities covered by the ADA, the Department of Justice regulations that implement the ADA provide additional guidance regarding the relationship between these requirements and elements that are not directly addressed by these requirements. Federal procurement law requires that ITMs purchased by the Federal government comply with standards issued by the Access Board under Section 508 of the Rehabilitation Act of 1973, as amended. This law covers a variety of products, including computer hardware and software, websites, phone systems, fax machines, copiers, and similar technologies. For more information on Section 508 consult the Access Board’s website at www.access-board.gov.
Advisory 707.1 General. If farecards have one tactually distinctive corner they can be inserted with greater accuracy. Token collection devices that are designed to accommodate tokens which are perforated can allow a person to distinguish more readily between tokens and common coins. Place accessible gates and fare vending machines in close proximity to other accessible elements when feasible so the facility is easier to use.
Advisory 707.4 Privacy. In addition to people who are blind or visually impaired, people with limited reach who use wheelchairs or have short stature, who cannot effectively block the ATM screen with their bodies, may prefer to use speech output. Speech output users can benefit from an option to render the visible screen blank, thereby affording them greater personal security and privacy.
- Audible tones shall be permitted instead of speech for visible output that is not displayed for security purposes, including but not limited to, asterisks representing personal identification numbers.
- Advertisements and other similar information shall not be required to be audible unless they convey information that can be used in the transaction being conducted.
- Where speech synthesis cannot be supported, dynamic alphabetic output shall not be required to be audible.
Advisory 707.5 Speech Output. If an ATM provides additional functions such as dispensing coupons, selling theater tickets, or providing copies of monthly statements, all such functions must be available to customers using speech output. To avoid confusion at the ATM, the method of initiating the speech mode should be easily discoverable and should not require specialized training. For example, if a telephone handset is provided, lifting the handset can initiate the speech mode.
- Machine location, date and time of transaction, customer account number, and the machine identifier shall not be required to be audible.
- Information on printed receipts that duplicates information available on-screen shall not be required to be presented in the form of an audible receipt.
- Printed copies of bank statements and checks shall not be required to be audible.
Advisory 707.6.2 Numeric Keys. Telephone keypads and computer keyboards differ in one significant feature, ascending versus descending numerical order. Both types of keypads are acceptable, provided the computer-style keypad is organized similarly to the number pad located at the right on most computer keyboards, and does not resemble the line of numbers located above the computer keys.
Advisory 708.1 General. Devices that do not require handsets are easier to use by people who have a limited reach.
Advisory 708.2 Audible and Visual Indicators. A light can be used to indicate visually that assistance is on the way. Signs indicating the meaning of visual signals should be provided.