Do you currently have motorcycle insurance? Insurance is mandatory to drive in California Yes I have insurance. But please show me your best quotes. No, please help me find the best insurance. Question What is another name for the service line? Answers The signal line The cable line The surplus line The power line Explanation The trailer service air line is also referred to as the control line or signal line. Take a FREE Practice Test Now This questions appears in the following tests: Mississippi Double , Illinois Combination , Indiana Combination , New Jersey Combination , Utah Combination ,