A free app for Android, by Headset Button Remapper.
Smart Headset Assistant – Phone Remote Control is a utility that allows you to make and receive calls using your headset, instead of your smartphone.
It allows you to set up a personal voice menu and navigate through it with the buttons of your headset.
It is compatible with most smartphones and can also be used with a variety of different headsets.
It has an interactive interface that allows you to make and receive calls by using the buttons of your headset.
It allows you to listen to notifications and make calls without having to touch your smartphone.
It is designed to be used while commuting by public transport, driving, riding a bike, or a motorcycle, doing sports like jogging, during a workout in the gym, etc.