Loud telephones were designed to help the hard of hearing manage their hearing loss. They provide unique features which are aimed to provide improved functionality for those with hearing loss, the deaf or those simply needing an extra loud phone (e.g. construction sites, heavy industry or domestic environments with background noise).
For The Hearing Impaired:
Phone amplification has two forms, extra loud volume of speech and extra loud ringtone. Most phones in this category have both features with each function separately adjustable so that speech may be adjusted more than the ringtone or vice versa. Some devices also have an additional tone control feature which enables personalisation where the volume can be focused on different frequencies such as high frequencies that enable easier speech recognition. While others also feature telecoil compatibility for those who wear hearing aids.
For The Visually Impaired:
Most phones for the hearing impaired also offer additional sensory clues which are useful for those with impaired eyesight. These take the form of backlit keypads which illuminate when the keypad is pressed, big buttons, flashing lights and photo caller ID.