Category 3 cable — commonly called Cat3 — is an unshielded twisted pair (UTP) cable designed for voice communications. For DFW businesses still running traditional analog phone systems or supporting older PBX equipment, Cat3 remains a cost-effective choice for single-line voice drops. Most business desk phones require only a single pair of conductors to operate, making Cat3 adequate for those applications.
Originally rated for data speeds up to 10 Mbps under 10BASE-T Ethernet, Cat3 has been largely replaced by Cat5e and Cat6 for any data application. BICSI installation guidelines recommend Cat3 only for legacy voice circuits, not new data infrastructure.