Bob CarrollA layman’s explanation of Line Security
You are a parent and your daughter is about to leave on her first long-distance driving trip. You’ve given your permission and you know she is a good driver; still you are apprehensive because she must make the drive overnight and alone.
Your daughter will have her cell phone with her and she promises that if she has any trouble at all on the long drive she will not hesitate to call you; and also that she will call you as soon as she arrives at her destination.
