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Presenter(s)
Gregg Vanderheiden Ph.D.
Trace Center
1550 Engineering Drive
Madison, WI 53706
608 263-5788
Email:GV@Trace.wisc.edu
The move from traditional telephones to Voice over Internet Protocol (VoIP) is happening rapidly and bringing new benefits but also new barriers if we are not prepared.
Possible New Barriers or Problems with People with Disabilities
Because of the way the law is constructed today, most of the protections for disability access are attached to the definition of telecommunication in the Telecommunication Act and in the FCC's interpretation of the term. To date, the FCC has interpreted information going over the internet as being 'information service' not 'telecommunication'. If all telecommunication shifts to internet telephony, the current FCC interpretations would result in the loss of most of the accessibility protection. It could also result in the loss of all of the financial support for special devices to facilitate communication and for support of the relay services, etc. which are all tied to revenues generated by telecommunication.
Text Telecommunication
Another problem area is text communication by people who are deaf. Although text over IP can be much more robust and flexible than analog TTY, there currently is no one method being adopted to transport text over the internet. The one overwhelmingly endorsed by consumers in a relatively new text standard called T-140, which, if transmitted in a form that provides delivery assurance (e.g., TCP/IP) or redundancy (eg.,RFC2793 with redundancy) can provide robust, reliable, simultaneous two way text with simultaneous voice capabilities. However, two variants of T-140 have now been introduced (text/T140 and audio/T140). In addition, some companies prefer to just ship the TTY tones over the network, either unprotected (and thus, subject to packet loss and packet delay) or using some encoding and decoding methodology. Unfortunately, the latter approach requires that whoever is receiving the text also have some method for dealing with the TTY tones and changing them back into text (rather than simply being able to display the text as would be true with the T-140).
The greater problem though is the multiple standards. Because there are multiple standards and no one standard is required, the path we're currently on could result in individuals who are deaf being able to communicate with other people who are using the same technology as they are. They would not be able to communicate reliably or at all with others. Ordinarily, market pressures would prevent deployment of a system where people could only make phone calls to people who had similar equipment to theirs. However, market pressures are not sufficient to address the needs of individuals who are deaf. In the absence of any action by the various industries involved to work in a coordinated and interoperable fashion, some type of regulation is going to be needed, or there will not be reliable, interoperable text communication for people who are deaf, severely hard of hearing or those with speech disabilities that require them to communicate in text.
Home Gateways
Another challenge comes in the form of home gateways. If we take a house that is wired for analog telephones, it is possible to install a box at the point where the telephone wire first enters the house. This box converts the analog telephone system in the house to an IP signal outside of the house. Thus, without changing any of the phones or the wiring in the house, it is possible to take advantage of IP communication phone rates, etc. You pick up an analog phone in the house and make a call. The IP gateway on the edge of your house changes it to an IP text call and sends it out over the IP network.
Unfortunately, IP text techniques such as T-140 will not work in this house because they only work on IP lines. Thus, a traditional TTY would need to be used in the house. However, as soon as it gets to the gateway, the TTY would have to be changed into IP text, or else the TTY signals would be sent out over the internet as an unprotected audio signal. This would result in un-reliable communication due to packet loss and delay.
As a result, neither analog nor IP text communications would work well in this house. You would either have to maintain a second regular phone line to the house to use with TTYs or you would have to bring IP (internet) connections into the house and install them wherever it would be desirable to make and receive text phone calls. Transcoding of IP text to TTY could be done at the gateway boxes. However, this is not what is being discussed by industry and it is not currently required.
Hard of Hearing
Another potential area of difficulty is individuals who are hard of hearing. IP technologies can provide a much higher fidelity and at least, temporarily, IP technologies have resulted in louder signals since there is no attenuation of the voice signal over distance when it is sent as data. However, when lossy compression techniques are used to save money (use bandwidth more efficiently), telephone conversations can be more difficult to understand. The exact nature of this problem has not yet been quantified and the continual introduction of new codecs (coding and decoding software) makes this a difficult area for us to get our hands around at this time.
Potential Benefits of IP Telecommunication
If regulations can be straightened out so that IP telecommunication is made accessible, then there are a wide range of different advantages of IP over traditional telecommunication.
First, it is possible to have multiple communication streams occurring simultaneously. This has a number of implications including:
1) Text can be traveling in both directions at the same time so people can communicate, argue, and interrupt just as with voice calls. (progress?)
2) You can have a voice conversation with a text translation (captioning) occurring simultaneously. This allows individuals who are hard of hearing to hear all of the tones and inflections of speech, while still being able to see the captions so they can understand what is being said.
3) A video can be added to text and audio, so that people can see each other as well. This facilitates communication for people with hearing or cognitive disabilities as well as allowing people to use gesture or sign language to communicate.
4) An individual who is blind could participate in a video conference, yet call up an assistant to describe what is happening visually whenever needed.
5) Teleconferences could be constructed so that the different participant's audio streams flow separately, so that an individual with a hearing impairment could turn down the volume on all but the stream which represents the person who is talking, thus eliminating background noise, and make it much easier to understand what is being said.
6) Mechanisms for allowing people to raise their hand can run in parallel with an audio teleconference so that individuals who cannot respond quickly or who are always a bit behind the conversation (because they are deaf and it is being translated for them) can be able to get in line and not have to try to jump into the short gaps between speakers.
7) In addition to these kinds of strategies which can be easily predicted, there are likely to be numbers of other ways IP telecommunication can facilitate interaction participation by people with disabilities. One somewhat controversial technique allows people with disabilities to project and alternate persona that looks and sounds different from them for those situations where they would otherwise be discriminated against.
Summary
The switch to PSTN to VoIP represents a major sea-change in telecommunication and it will dramatically alter what is possible and how we communicate with each other. It will perhaps be even more dramatic and sudden shift than the introduction of the internet. The internet came in as a new capability that ran alongside of, but did not actually displace, other information technologies (although it did over time change their usage). The switch from PSTN to VoIP is likely to occur in a replacement fashion. That is, when a company switches from PSTN to VoIP, the PSTN disappears the same day the VoIP…. If the housing unit switches to or implements VoIP, it is unlikely that there will be analog PSTN lines strung in the same building. Thus, individuals will often not have the option of using either VoIP or PSTN, depending on which works better for them. They will have to use which ever technology is at the airport, in the building, or even in their community as VoIP replaces PSTN. And the rate at which this is happening is surprising.
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