Category 2 cable, or simply Cat 2, is a misnomer, probably adopted by those who assumed that the Telecommunications Industry Association

Telecommunications Industry Association

The Telecommunications Industry Association is accredited by the American National Standards Institute to develop voluntary, consensus-based industry standards for a wide variety of ICT products, and currently represents nearly 400 companies...

 set up "Categories" for all types of cables originally defined by Anixter

Anixter International

Anixter International is a Fortune 500 company based in Glenview, Illinois, USA and founded in 1957. Anixter is a leading global supplier of communications and security products, electrical and electronic wire and cable, fasteners and other small components. Anixter has physical presence in 52...

, the distributor, under the grades called Levels. TIA-568 only recognized cables of Category 3

Category 3 cable

Category 3 cable, commonly known as Cat 3 or station wire, is an unshielded twisted pair cable designed to reliably carry data up to 10 Mbit/s, with a possible bandwidth of 16 MHz...

 ratings or above. Anixter Level 2 was a grade of UTP cable capable of transmitting data at up to 4 Mbit/s. It is the first cable which can transmit voice and data up to 4mbps. Anixter Level 2 cable was frequently used on ARCnet

ARCNET

ARCNET is a local area network protocol, similar in purpose to Ethernet or Token Ring. ARCNET was the first widely available networking system for microcomputers and became popular in the 1980s for office automation tasks...

 and 4 Mbit/s token ring networks, it is also used in telephone networks but it is no longer commonly used.