HYAC is a self-supporting urban telecommunication cable with solid polyolefin insulated copper conductors and a moisture-barrier PE jacket. The insulated copper conductors are twisted into pairs, and the pairs are stranded into the cable core. An aluminum-plastic composite tape is applied longitudinally as the moisture barrier, followed by a PE jacket, and the whole is integrated with a steel wire strand inside a figure-8 PE jacket to form the cable. It is mainly used for transmitting audio, analog signals at 150kHZ and below, and digital signals at 2048kbit/s and below. Under certain conditions, it can also be used to transmit digital signals above 2048kbit/s.