t is a dedicated 9-pin cable. 3 twisted pairs transfer voice and data control, 1 twisted pair supply power and 1 line is for auxiliary audio. The cable constitutes 64-pin copper shield foiled by aluminum, aluminum shield with waterline shield, it can prevent malicious interference and eavesdropping. Moreover twisted pairs guarantee frequency and security of data transmission. Thus electromagnetic interference towards interface is minimized. The outer shield is made by high elastic PVC which is no toxin, high flexibility, light weight and low flammability. Thus the cable is easy installation, low failure rate, high aging resistance and reliability. It fulfills RoHS and American UL standard. Hand-in-hand cable with twisted pair design makes the whole system use fewer cumbersome cables and be installed conveniently.