What gauge is cat3 cable?

Category 3 (Cat3) is a type of unshielded twisted-pair (UTP) cable. Category 3 refers to specifications that describes an ability to operate at frequencies of up to 16MHz. It was the cable of choice in the early days of twisted-pair Ethernet since it was designed to reliably transmit up to 10Mbit/sec. Though now eschewed in the Ethernet world in favor of Cat5e and Cat6, Cat3 still makes a very useful cable for telephone and Voice-over-IP applications.