The signal cable mainly refers to the line in the electrical control circuit for transmitting the sensing information and the control information. Signal lines are often a number of cable lines constitute a bundle or multiple transmission lines, can also be arranged in the printed circuit board in the printed line, with the technology and application of continuous progress, the signal line has been developed by the metal carrier for the other Carrier, such as cable. Different use of the signal line often have different industry standards, in order to standardize the production and application.