Remote Infrared Audible Signage
(RIAS) was developed by Smith-Kettlewell Eye Research Institute
(as Talking SignsR http://www.talkingsigns.com
) so that print-handicapped people, such as those that are blind
Blindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
or have low-vision, or are illiterate, foreign, or visually impaired, would be able to access the same type of information available through textual print signs within the built environment.
It consists of infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
transmitters repeatedly sending encoded spoken versions of the contents of the sign through wireless
Wireless telecommunications is the transfer of information between two or more points that are not physically connected. Distances can be short, such as a few meters for television remote control, or as far as thousands or even millions of kilometers for deep-space radio communications...
communication. An early version
developed in 1979 called "Talking Lights" has been successfully upgraded/marketed commercially as "Talking Signs" which are being globally installed.
An associated handheld or glasses
Glasses, also known as eyeglasses , spectacles or simply specs , are frames bearing lenses worn in front of the eyes. They are normally used for vision correction or eye protection. Safety glasses are a kind of eye protection against flying debris or against visible and near visible light or...
-mounted IR receiver is directionally sensitive to a direct, line-of-sight
Line-of-sight propagation refers to electro-magnetic radiation or acoustic wave propagation. Electromagnetic transmission includes light emissions traveling in a straight line...
infrared light beam and orients the person by giving more positive feedback
Feedback describes the situation when output from an event or phenomenon in the past will influence an occurrence or occurrences of the same Feedback describes the situation when output from (or information about the result of) an event or phenomenon in the past will influence an occurrence or...
when the sign is being pointed to directly and is close.
The system has been tested and works effectively in both interior and exterior settings and does not disturb those environments because the IR beams are invisible and silent.
The principle of Alexander Graham Bell
Alexander Graham Bell was an eminent scientist, inventor, engineer and innovator who is credited with inventing the first practical telephone....
The photophone, also known as a radiophone, was invented jointly by Alexander Graham Bell and his then-assistant Charles Sumner Tainter on February 19, 1880, at Bell's 1325 'L' Street laboratory in Washington, D.C...
led to development of devices capable of transmitting/decoding infrared waves in systems ranging from military communications through remote control systems for televisions and computers.
RIAS features in US building code 703.7. This is quoted in a report
for the U.S. Access Board as follows:
- 703.7.1 General: Remote Infra red Audible Sign Systems shall comply with Section 703.7.
- 703.7.2 Transmitters: Where provided, Remote Infra red Audible Sign Transmitters shall be designed to communicate with receivers complying with Section 703.7.3.
- 703.7.3 Remote Infra red Audible Sign Receivers.
- 703.7.3.1 Frequency: Basic speech messages shall be frequency modulated at 25 kHz, with a +/– 2.5 kHz deviation, and shall have an infra red wave length from 850 to 950 nanometer (nm).
- 703.7.3.2 Optical Power Density: Receiver shall produce a 12 decibel (dB) signal–plus–noise–to–noise ratio with a 1 kHz modulation tone at +/– 2.5 kHz deviation of the 25 kHz subcarrier at an optical power density of 26 picowatts per square millimeter measured at the receiver photosensor aperture.
- 703.7.3.3 Audio Out-put: The audio out-put from an internal speaker shall be at 75 dBA minimum at 18 inches (455 mm) with a maximum distortion of 10%.
- 703.7.3.4 Reception Range: The receiver shall be designed for a high dynamic range and capable of operating in full sun background illumination.
- 703.7.3.5 Multiple Signals: A receiver provided for the capture of the stronger of two signals in the receiver field of view shall provide a received power ratio on the order of 20 dB for negligible interference.