Cox vs Quantum Fiber is now really Spectrum vs AT&T. Charter, which runs Spectrum, completed its purchase of Cox in August 2026, and AT&T bought Quantum Fiber from Lumen on February 2, 2026.[1][2] CenturyLink is a third name in the mix: Lumen kept its copper DSL customers, so a CenturyLink quote may not be fiber at all.[2]
Comparison pages written before 2026 describe three independent companies. This guide sorts out which product you are actually being offered before you compare prices.
Which company is on your quote?
Lumen sold its consumer fiber business in eleven states, Quantum Fiber included, and kept its copper-based consumer services.[2] Quantum Fiber's own location list includes Arizona, Nevada and Nebraska, which hold the main Cox overlap areas in our FCC data.[3][4]
| Name on the quote | What it usually means now | Ask before comparing |
|---|---|---|
| Cox | Your existing plan, now run by Spectrum | When does my current price end? |
| Spectrum | Spectrum's own packages in former Cox areas | What is the price for internet alone? |
| Quantum Fiber | Fiber service owned by AT&T | Is my address fully fiber? |
| CenturyLink | Lumen service, fiber in some places, copper DSL in others | Is this fiber or DSL, and what are both speeds? |
Sources for the table: the Lumen sale filing, Charter's transaction page and CenturyLink's plan page.[2][1][5] If you searched for CenturyLink vs Cox, the right comparison depends on that last row. Our DSL explainer covers what copper service can and cannot do.
Where the two overlap
Our FCC data (filings as of December 30, 2025, before either deal closed) lists Lumen and Cox together in Phoenix, Tucson, Mesa, Chandler, Gilbert, Glendale, Scottsdale, Tempe and Peoria in Arizona; Las Vegas, Henderson and North Las Vegas in Nevada; and Omaha, Nebraska.[4] Charter names Las Vegas and Phoenix among the former Cox markets it now serves.[1]
Lumen's FCC listing covers both fiber and copper, so it cannot tell you which one reaches your home.[4] Run the address check on Quantum Fiber's site and ask Spectrum to confirm the same address.
If you have Cox today
Charter's August 20, 2026 customer letter said Cox customers would see no pricing or service changes at that time unless they asked for them, and could keep their current plan.[1] Since September 16, 2026, former Cox customers can also switch to Spectrum's products and pricing.[6]
Spectrum's welcome offers lean on mobile. Internet customers without Cox Mobile can get a year of Spectrum Mobile free, and Spectrum says households bundling internet with two mobile lines save more than $1,000 in the first year or it makes up the difference.[6] Spectrum's internet comes with no data caps.[6] Its customer service commitments are due to reach former Cox areas later, not immediately.[1]
Spectrum did not publish standalone internet prices in that release, so get a written quote for internet alone and another with mobile lines.[6] Our AT&T vs Cox guide covers the same Cox options against AT&T's own fiber and Internet Air.
What Quantum Fiber offers in these markets
Quantum's Phoenix page listed up to 500 Mbps at $50 a month and up to 1 Gig at $50, shown as $25 off $75, after a $5 discount for AutoPay from a bank account; paperless billing is required and taxes and fees are extra.[7] Multi-gig tiers included 3 Gig at $70 and 8 Gig at $165 a month.[7]
Quantum includes Wi-Fi 7 equipment at no monthly charge for an initial period, so ask what happens after it.[7] Most plans have equal upload and download speeds, a real difference from cable if you upload often.[7] Quantum also lists no annual contract and unlimited data.[3]
Where CenturyLink fits
CenturyLink's site still advertises Fiber Internet up to 500 Mbps for $50 a month and up to 940 Mbps for $75, in select locations, with paperless billing.[5] That rate excludes a CenturyLink fee of up to $1.50 a month, and CenturyLink says a credit check or deposit may apply for postpaid service.[5]
If your CenturyLink offer is DSL rather than fiber, compare its quoted speed with Spectrum's slowest tier and with Quantum Fiber, if Quantum reaches your street.
Switching checklist for a two-owner market
- Confirm the address on Quantum Fiber's checker and with Spectrum before cancelling anything.
- Ask Spectrum whether moving from your Cox plan to a Spectrum plan changes your equipment.
- Ask Quantum how long its new-customer discount lasts and what the standard rate will be.
- Schedule the new installation before ending Cox or CenturyLink service.
- Return old equipment and keep the receipt.
Our switching guide explains how to overlap service so you are not left offline.
Our verdict
Stay with your Cox plan if it works and its price is fair; Charter says you can.[1] Move to Spectrum's packages if you will bring mobile lines and the written total is lower. Choose Quantum Fiber if it is confirmed at your address and upload speed or a low entry price matters to you. Treat a CenturyLink DSL quote as a fallback, not an equal to either.
The call line below is for comparing plans before you buy. It is not support for an existing Cox, Spectrum, Quantum Fiber or CenturyLink account.
Frequently asked questions
Is Cox still a separate company?
No. Charter's customer letter says Spectrum completed its acquisition of Cox in August 2026.[1]
Is Quantum Fiber still part of CenturyLink?
No. Lumen, CenturyLink's parent, sold Quantum Fiber to AT&T on February 2, 2026, keeping its copper service.[2]
Does Quantum Fiber have data caps?
Quantum lists unlimited data and no annual contract.[3]
Sources
- Charter Acquires Cox: A New Era in Connectivity. Charter Communications, Charter Acquires Cox transaction page and customer letter of August 20, 2026, accessed October 20, 2026. Completion, options for Cox customers, commitment timing and former Cox markets. ↩
- Lumen Completes Sale of Consumer Fiber-to-the-Home Business to AT&T (SEC Form 8-K Exhibit 99.1). Lumen Technologies, Lumen Completes Sale of Consumer Fiber-to-the-Home Business to AT&T, SEC Form 8-K Exhibit 99.1, February 2, 2026, accessed October 20, 2026. Sale completion and retained copper services. ↩
- Quantum Fiber: All Quantum Fiber Locations. Quantum Fiber, All Quantum Fiber Locations, accessed October 20, 2026. State list, contract and data terms. ↩
- FCC National Broadband Map, Broadband Data Collection. FCC Broadband Data Collection, D25 filing as of December 30, 2025, via our place-level provider data, accessed October 20, 2026. Area-level listings only. ↩
- CenturyLink Internet. CenturyLink, Internet plans page, accessed October 20, 2026. Fiber prices, CTL fee, billing and credit check terms. ↩
- Spectrum Says 'Hi!' to 11+ Million Homes and Businesses. Charter Communications, Spectrum Says 'Hi!' press release, September 16, 2026, accessed October 20, 2026. Spectrum pricing launch in former Cox markets, mobile offers and savings promise. ↩
- Quantum Fiber: Fiber internet in Phoenix, AZ. Quantum Fiber, Fiber internet in Phoenix, AZ, accessed October 20, 2026. Local plan prices, payment conditions, equipment period and upload speeds. ↩
Written with AI assistance and checked against the sources listed; our data from FCC/Census as dated. FCC data as of December 30, 2025; Census ACS 5-year 2020-2024. Editorial policy