We live on 13 acres along with our business. I am caring for 92 yo parents. They have become increasingly dependent on me. Dad doesn't know how to use phone and Mother is beginning to have problems too. Is there some device that is simple for them to contact me while I am at my business about 1,500 feet from our home. Preferably not a 2-way radio, but an intercom of sorts. Any advice would be appreciated.