I’ve written previously about the importance of the correct type of feedback for input, especially when one or more of your senses fail you.
This SENS phone uses a combination of tactile sensors and audio feedback to the user. When a person key is pressed the phone informs the user and waits for a second press before taking it as an input. A click sounds when completed as well. For low vision users there is varius llumination for various status messages about the phone.