Like most Internet providers which are also historic landline telephone monopolies, AT&T’s last-mile network is anchored by switching centers called “central offices” (COs).  AT&T’s central offices are buildings that house centralized switching equipment for the areas they serve (historically, “exchanges”) and local nodes of the company’s fiber backbone network. They also serve as home bases for service personnel and equipment, and sometimes as office space for other staff.

AT&T COs are generally three to six miles from each other, in neighborhood locations throughout bigger cities, and in suburban town centers.

There are thirty AT&T central offices in Cuyahoga County.

“Distance to the central office” and Internet speed. AT&T’s legacy ADSL network connects each customer directly to a switch in the central office via a dedicated copper line, often at a distance of a mile or two, sometimes more. Longer transmission distances over copper mean significantly slower download and upload speeds; so in an ADSL network, a customer’s “distance to the central office” is a major determinant of the quality of service.

Fiber-to-the-node networks reduce this copper “line loss” problem by moving the fiber-connected switch much closer to the customer, plus improving the switch itself. Fiber-to-the-premises networks eliminate the problem altogether, by eliminating the copper.