Many phones now have a volume control. Some are specially designed for people with a hearing loss. The most powerful of these may amplify the signal as much as 50 decibels. Some phones also have other special features of interest to people with a hearing loss such as:
- mini-plug jack for plugging in a:
- frequency control
- extra loud, frequency adjustable ringers.
Phones that do not have amplifiers built in can usually be adapted with an add-on telephone amplifier.
Most amplified phones (and many others, too) are also "Hearing Aid Compatible" (HAC), which means that their speakers generate a magnetic signal that can be "heard" by a hearing aid's telecoil.