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Copyright © 2007 Avaya Inc. All rights reserved Accessible Telecommunication Systems Paul R. Michaelis, Ph.D., C.P.E. February 2007.

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Presentation on theme: "Copyright © 2007 Avaya Inc. All rights reserved Accessible Telecommunication Systems Paul R. Michaelis, Ph.D., C.P.E. February 2007."— Presentation transcript:

1 Copyright © 2007 Avaya Inc. All rights reserved Accessible Telecommunication Systems Paul R. Michaelis, Ph.D., C.P.E. February 2007

2 2 The goals of this presentation Describe assistive technologies that are commonly used in conjunction with telecom systems. Summarize the telecom-related laws and regulations that apply to the manner in which you support your employees and customers with disabilities. Describe accessible solutions that have been developed by Avaya, allowing you to see for yourself that accessible solutions don’t have to be expensive, complicated, or hard to administer. Describe how Avaya accessible solutions can be of benefit to you and your customers.

3 3 Avaya’s accessibility philosophy Many of the people in Avaya who are working on accessible solutions have personal reasons for regarding it as important. We will not achieve our personal objectives if our solutions are adopted solely by organizations for whom Section 508 is mandatory. In the private sector, the incremental costs and perceived complexity of accessible solutions are disincentives to the hiring of a qualified person with a disability. For these reasons, whenever it is possible to do so, we embed our accessibility solutions within our mainstream products, and provide these solutions at no additional charge.

4 4 A quick review of assistive technologies: (1) What is a TTY?

5 5 What is a TTY? A TTY (also known as a TDD) is a special text terminal that lets people who are deaf, hard of hearing, or speech-impaired use a telephone to communicate.

6 6 Some TTY basics How US TTYs work: –FSK “Baudot” tones. Half duplex. No error correction; no “handshake”; no carrier tone. (TTYs are silent when not transmitting.) There is no ability to interrupt the other person. –45.45 baud. (Each “bit” is a 22ms tone, either 1400 or 1800Hz.) –Each character consists of seven tones: a start bit at 1800Hz, five tones at 1400 or 1800Hz that specify the character, and 1.5 stop bits at 1400Hz. Not all TTY users transmit and receive with their TTYs. In fact, roughly half have hearing deficits, but still speak clearly; these users often prefer to receive via TTY but then speak in response. This is commonly referred to as Voice Carry Over or VCO.

7 7 (2) What is a Telecommunication Relay Service?

8 8 Telecommunication Relay Service The purpose of a Telecommunication Relay Service, or TRS, is to be a “translator” between voice-based users of telecom equipment and people who cannot use traditional telephones because they are deaf, hard of hearing, or unable to speak clearly. (In most parts of the US, relay services may be accessed by dialing ) Is it acceptable for an enterprise, health care organization, or government agency to require people to communicate via TRS? Some points to consider: In calls that are placed via TRS, an intermediary unknown to either party is given access to information that the parties may wish to protect. Examples include account numbers, credit card numbers, passwords, and confidential medical information. Ask your customers: Is the use of TRS an invitation to identify theft? Even if HIPAA compliance and identity theft were not a concern, would you be comfortable discussing medical issues with your doctor if you knew that a stranger was listening to the conversation?

9 9 (3) What is inductive coupling ?

10 10 Inductive coupling If an object gets within a few inches of most hearing aids, the aids often emit a loud howling sound. This is simple acoustic feedback, similar to the feedback you can get with an auditorium P.A. system. To prevent this when a phone is being used, the microphone in the aid must be turned off. (Note: The microphone is turned off, but not the hearing aid itself.) The voice signal from the phone handset is transmitted to the aid via electro-magnetic inductive coupling. Starting in 1989, all telephone handsets manufactured or imported for use in the US must be “hearing aid compatible” – i.e., they must support inductive coupling. The inductive coil in the assistive listening device that receives the signal is commonly referred to as a tele-coil or T-coil. Note: 1.FCC “hearing aid compatibility” regulations do not apply to headsets. 2.The electro-magnetic “noise” produced by many wireless devices (especially GSM phones) can interfere with the inductive coupling.

11 11 Relevant US laws and regulations

12 12 First generation of disability access laws Architectural Barriers Act of 1968  First accessibility law; governed physical barriers (doors, stairs, etc.) in transportation facilities and Federal buildings. Hearing Aid Compatibility Act of 1988  Requires the Federal Communications Commission (FCC) to ensure that all telephones manufactured or imported for use in the United States after August 1989 are hearing aid compatible. Americans with Disabilities Act of 1990  Permits people with disabilities to file civil lawsuits in order to obtain “reasonable accommodation.” These lawsuits can be expensive for individuals to pursue, which is why many ADA cases are class actions. Within the ADA, there are very few explicit requirements for telecom equipment.

13 13 Examples of recent telecom-specific laws Section 255, Telecommunications Act of 1996 Empowers the Federal Communications Commission to require disability access provisions in telecom equipment and services. Section 508, Rehabilitation Act of 1973 (As amended in 1998) Adds specific accessibility requirements to Federal procurement regulations.

14 14 ProblemsandSolutions

15 15 A closer look at four Avaya products  TTY-on-VoIP  TTY Messaging  TTY IVR  Universal Access Phone Status In all four cases, we did the following:  Identify the users’ needs.  Identify capabilities that already existed within the “plain vanilla” versions of the products, that we could leverage in order to build the accessibility adjuncts.  Because we were able to piggyback onto other solutions that already existed, we have been able to provide these accessibility adjuncts for free.

16 16 What happens when TTYs are used with IP telephones? Problem #1: Packet loss Most VoIP systems have voice-optimized packet loss concealment algorithms that work by tricking the human ear into hearing something that really wasn’t there. For voice, packet loss rates as high as 5% are usually tolerable. Unfortunately, if a TTY device does not receive the complete set of tones that comprise a character, it cannot be expected to display that character correctly. Some quick math: –The sequence of tones for a single TTY character is 165 milliseconds in length. –A typical VoIP audio packet is 20 milliseconds. This means that a TTY character spans a little over eight audio packets. –It also means that, with a packet loss rate of just one percent, approximately eight percent of TTY characters might not be received properly.

17 17 What happens when TTYs are used with IP telephones? Problem #2: Audio compression VoIP systems often use voice-optimized audio compression techniques (such as G.729) in order to squeeze additional conversations onto the same set of wires. Unfortunately, these techniques can distort TTY tones so badly that the TTYs become unusable. An example of how audio compression might be tolerable in a voice conversation, but harmful to a TTY: –If a portion of a word was spoken for 22 milliseconds, but reproduced for the listener for 20 or 24 milliseconds, would anyone notice? Probably not. –By contrast, if the 22-millisecond start tone of a TTY character was played for a receiving TTY for 20 or 24 milliseconds, the receiving TTY would probably be unable to decode the character.

18 18 The expensive solution Configure your IP network with enough extra capacity to permit all VoIP calls to be carried uncompressed with no packet loss. Why all calls? Because you never know in advance when someone might decide to use a TTY.

19 19 The Avaya TTY-on-VoIP solution  Problem: The voice channels on VoIP systems may be unable to transport TTY tones reliably.  Users’ needs: People must be able to use standard TTYs. It must be possible to intermix text and voice on the same call.  Key capability that already existed: VoIP systems use a non-audio mechanism (“RFC-2833”) to transport “touch tone” signals.  The solution:  Detect automatically when a TTY is in use.  Use RFC-2833 protocol to transmit a description of the tones (rather than the tones themselves). Command the receiving system to reconstruct those tones for the TTY at the far end.  Transmit each RFC-2833 packet many times. (Unless packet loss is especially severe, at least one of them will get through.)

20 20 Avaya TTY messaging  Problem: If someone calls you, and you don’t answer your phone, the call gets forwarded to voic . What if it’s a TTY user?  Users’ needs: Callers must be able to choose whether they wish to be prompted by voice or in TTY format. Regardless of the prompting style they choose, they must be able to leave a voice or TTY message.  Key capabilities that already existed: (1) The ability to let callers choose the spoken language for prompting; (2) the ability to record and play back TTY tones reliably.  The solution:  Create a TTY “announcement set” in exactly the same way that spoken announcement sets are created, i.e., by generating audio recordings of the prompts and menus that must be presented to users.

21 21 Avaya TTY IVR  Problem: 1.Typical IVR (Interactive Voice Response) systems require people to use the telephone’s “touch-tone” keys in order to make menu selections or enter data. Some of the better systems, including Avaya’s, also support automatic speech recognition. 2.Many people who use TTYs are unable to speak and unable to transmit touch-tones because their TTY devices switch automatically from touch-tone mode to Baudot mode after dialing a phone number.  Users’ needs: Callers must be able to use Baudot TTY signals in order to make menu selections and enter data.  Key capability that already existed: Automatic speech recognition.  The solution: Modify the ASR mechanism to enable the detection and decoding of Baudot TTY signals.

22 22 Universal Access Phone Status  Problem: Business phones use LCDs and LEDs to provide info.  Users’ needs: People with visual impairments cannot get important info, such as caller ID, whether the phone is forwarded, which lines are in use, and whether someone on hold has disconnected.  Key capability that already existed: The patterns and changes that occur in a phone’s display can only mean one thing. For example,  Only one thing can cause the LED associated with button #1 to go from steady-on to flashing: “Line 1 on hold.”  Only one thing can cause the LED associated with button #3 to go from flashing to off: “Caller on Line 3 has disconnected.”  The solution: user-customizable PC-based software that  Logs into the same “socket” on ACM that IP Softphone uses.  Uses “shared control” to monitor the telephone’s state table.  Provides by voice a description of the info in the state table. 

23 23 The newest member of the family: The Avaya IP Office Accessibility Suite The only telecom system for the SMB market that qualifies for the IRS “Disabled Access Tax Credit” (Form 8826). Under the right circumstances, small businesses that acquire an IP Office can reduce their Federal taxes by $5,000.


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