The problem sometimes occurs at hotels, which loan amplifiers to customers, to use with their room phones. The cause is related to the type of handset microphone and circuitry being used. The solution may involve obtaining a universal amplifier, which is designed to work with most types of phones. TTYs allow users to read the text of their phone conversations. Some TTYs specifically designed for voice carry-over do not include a keyboard.
Cellular phones offer users both convenience, and security.
Hard of hearing consumers also desire a vibrating ringer, available on select models. Digital wireless phones have generally not been shown to work reliably with hearing aids or TTYs at this time, although the industry is working towards a solution for both. Most pagers can vibrate and some display the text of messages. The Internet is especially a boon to hard of hearing people because it can be used for instant messaging, conference calling and e-mail. New developments in text telecommunications include videophones, text based office intercom systems and TTY accessible interactive voice response systems.