Cell phone service used to be in analog format, which works with TTYs and hearing aids. However, this is being phased out and replaced by new digital wireless phones. Digital technology is more efficient and secure, with less static and better voice quality. Unfortunately, digital cellular phones not only can cause hearing aids to buzz, they also do not always carry TTY signals. The problems with hearing aids happen because hearing aid components act as antennae.
Digital phones send out pulsing energy.
The hearing aid demodulates the pattern of pulsing as a buzz. With TTYs, the problems happen because the TTY code is garbled , acoustic coupling is not effective, direct connections are not available, and there may be interference. Solutions could include developing a standard interface, decreasing frame error rates in transmission, and using digital services and modems. There are several types of digital technology.