Hearing-impaired people use devices called TTYs, or tele-typewriters, to make and receive calls on their home phones. The conversations are similar to the millions of exchanges that take place every day between users of instant messaging applications.
TTYs continue to work on most of today's landline telephone networks, which use analog equipment to convert sound into electricity. However, the estimated 4 million TTY customers say the same deviceswhen coupled with a cell phone, which uses a digital network to ferry calls and data.
"Isn't it funny that the more advanced technology gets, the less we can use it," said Dale Young, a lawyer and founding member of Hearing Impaired Professionals, based in San Francisco.
The Federal Communications Commission has given wireless carriers until June 30 to end the problem. The carriers will be subject to disciplinary action if they miss the deadline; fines will be determined by the commission.
With the deadline approaching, carriers have begun telling industry groups and the FCC that they indeed will be ready in time.
"We are confident we will meet this deadline," a representative for AT&T Wireless said Monday.
A TTY is basically a word processor. The letters typed into the machine are turned into electrical signals. When the signals reach their destination, they are converted back into letters, which appear on a display screen.
"All carriers have some phones in hand and software in a couple of switches in their networks, and they are testing," said Judy Harkins, professor of communication studies at Gallaudet University in Washington, D.C., which is helping test some of the phones expected to debut later this summer.
Harkins said the new technology, including a cell phone from Nokia that was unveiled at Comdex last year, breaks up the TTY signals into ones the digital networks can understand. Once the signals travel across the cellular carriers' networks, they are "unmasked" and returned to the signals the TTY can understand, she said.
Many hearing-impaired people use some form of wireless device capable of sending and receiving text, such as Research In Motion pagers. But they have proven to be a less-than-adequate substitute, Harkins said, particularly when trying to reach emergency services such as police or fire personnel.
"Pagers can't call 911," she said.