 costly for carriers than equipment required to interface with T1 circuits. Examples of carriers that offer Ethernet over Copper include AT&T, Windstream (the fifth largest incumbent carrier in the United States), and MegaPath. MegaPath also resells services to other, non-incumbent providers who then sell Ethernet over Copper to their own customers. Competitive carriers such as MegaPath install the Ethernet equipment in the central offices of incumbent telephone companies. It also supplies compatible Ethernet devices at customer locations. Hatteras Networks is one manufac- turer of Ethernet over Copper equipment. Many of its switches are multiplatform. It also supports other services such as T1 circuits. T1 AND T3: THE FIRST BROADBAND SERVICES FOR BUSINESSES T1 service is a digital broadband technology that utilizes a Time-Division Multiplex- ing (TDM) scheme which enables one circuit to carry 24 voice, video, or data chan- nels. The entire circuit runs at 1.54Mbps. T3 is also able to carry a variety of traffic types but operates at 44Mbps. TDM divides the T1 and T3 circuits' capacity by assign- ing each channel to small slices of time. When T1 was introduced, it had many times the capacity of the fastest modems available and was more efficient than managing the individual analog copper lines that it replaced. T1 service was first used in the United States to connect telephone company back- bone switches to one another over copper cabling. It was made available commercially to large financial services companies in downtown areas in 1983. An impetus for its wider availability was competition in the late 1980s from new providers who offered it at lower prices and in more locations than the incumbent telephone companies. Manufacturing efficiency, sharp increases in bandwidth demand, and wider avail- ability have led to more affordable T1 service. With some exceptions, T1 and T3 ser- vices are used worldwide. T3, another service based on TDM, operates at 44Mbps in North America. T1 and T3: The First Broadband Service