Definition

Wire center

Also known as: central office, CO, serving wire center

A wire center is the carrier facility — commonly called a central office — where copper subscriber loops for a defined geographic serving area terminate and are connected to the wider network.

How it works

Every copper pair in a serving area runs back to its wire center, where line equipment supplies dial tone and loop current and connects calls onward. Because the copper plant is organized around these facilities, carriers plan retirement wire center by wire center rather than customer by customer.

Why it matters

Retirement is announced at wire-center granularity, so whether a site is affected depends on which wire center serves it — not on the customer's size or preferences. Two locations a few miles apart can be on entirely different timelines.

Common use cases

Determining which sites in a portfolio are affected by a retirement filing
Sequencing migration by serving area rather than by site convenience

Wire-center granularity is the reason a single national migration date does not exist. A portfolio’s schedule is really a list of serving areas, each with its own clock.

Common misconceptions

“Copper retirement happens nationwide all at once.”

It proceeds wire center by wire center. A national portfolio will face many separate dates, which is precisely what makes multi-site planning difficult.

Frequently asked questions

How do I find out which wire center serves a site?

The serving carrier can identify it, and FCC copper retirement filings identify affected wire centers. Matching your site addresses against filings is how you find out which locations have a clock running.