http://www.lifelinesys.com/
This is the one we used. It works very good. $30 a month/$1 a day! There is a unit you where on your neck AND a box on a table also. You can push the button on your neck or table, and they answer. Whole separate thing, not with your phone. Your parent speaks from anywhere in house and she can be heard. If your parent pushes button but is not able to answer or speak someone is contacted and sent immediately. If your parent is able to speak and just wants Lifeline to contact the family members and have them call, this is what is done. See website, explains it better.