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Vol. 4, Issue 6, Nov/Dec 1996 |
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Do You See What I'm Saying?
Telephone Communication For Those Who Are Deaf Or Have Severe Hearing Loss
When Alexander Graham Bell invented the telephone in the late 1870's, no thought was given to giving people with hearing impairments access to the telephone. Generally, face-to-face communication is required by people with hearing impairments. This is accomplished through the use of sign language, lip reading, or written notes. These options are not suitable for telephone communication. Improved access became possible through the advancements in technology of the early 1960's. At the head of this list is the TTY/TDD. In 1964 Robert Weitbrecht developed the acoustic coupler. An acoustic coupler converts the electric signals of a teletypewriter (TTY) into audible tones that can be transmitted over telephone lines. The acoustic coupler, or modem, connects the teletypewriter to the telephone line. Connecting the telephone to the acoustic coupler is accomplished simply by placing the hand set on the rubber cups on the coupler. At about the same time as the development of the acoustic coupler, AT&T upgraded its equipment and donated their old teletypewriters to the deaf community. These TTYs used paper to display the typed telephone conversation. Some of the problems with these donated TTYs were that they were large and cumbersome, slow and, because of their age, prone to mechanical failures. In the early 1970's a smaller electronic version, the Telecommunication Device for the Deaf (TDD) was introduced. It was much smaller, about 9" by 12", lighter, about 2 to 5 pounds and portable. Some models also include rechargeable batteries available for use even on pay telephones. Many have their own carrying cases. Today, TDDs are available with memory for storage of telephone numbers and commonly used messages. Models with the direct connect feature require no additional telephone. In other words, there is no need to put the telephone hand set onto the TDD. The telephone line just plugs into the back of the TDD. These models can also act as answering machines.
There are two codes used in TTY/TDD communication. They are ASCII (ask - ee) and Baudot (baw - doe). These are like two completely different languages and cannot communicate with each other. If you have a device which uses only Baudot, you can't make a call to a device which uses only ASCII. Most TDDs today use Baudot, but some are capable of using both Baudot and ASCII. Both ASCII and Baudot have their advantages.
Baudot TDDs start around $240. ASCII is an option which adds about $50 to $60 to the cost. TDDs using ASCII are also able to communicate with computers using TDD software. Most TDDs distributed by state programs are able to communicate with both ASCII and Baudot. If you already own a computer, the cost of the upgrading a computer to be used as a TDD is comparable to the cost of a TDD. Using the proper communication software with the computer will allow access to a broad range of information sources in addition to the ability to use the computer as a TDD and can allow you to communicate with both ASCII and Baudot TDDs.
For additional information on TDDs you can contact the Assistive Technology Resource Center near you, or plan to attend one of the DATI's upcoming TDD workshops.
