I am looking for a device to enhance a person’s voice that is making a call on a landline phone. This would be for the person making the call as their voice is damaged and they talk very low.
I'm not sure if it will help in your case but many Panasonic handsets offer a feature called "Voice Enhancer" or "Voice Boost". The KX-TGM420W is one model and I suspect there are others.
