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The right CenturyLink modem comes down to two things: whether you have DSL or Quantum Fiber, and how fast your plan is. CenturyLink does not let you use just any modem, so the unit has to be on its certified list and matched to your speed tier. This guide pairs every CenturyLink plan with a tested, ready-to-activate modem, so you can skip the monthly rental fee and get the full speed you pay for. You do not need to be tech-savvy to follow it.
Key takeaways
- CenturyLink only works with certified modems. Unlike cable internet, you cannot use a random retail modem on CenturyLink DSL or Quantum Fiber. The modem must be on CenturyLink's approved list, which is why a tested, compatible unit matters.
- Match the modem to your speed tier. Single-line DSL (up to 100 Mbps), bonded DSL (up to 140 Mbps), and Quantum Fiber (500 Mbps to 1 Gig) each call for a different modem. The table below shows the right pick for each.
- Owning your modem ends the rental fee. CenturyLink DSL customers pay about $15 a month to lease a modem, roughly $180 a year. A compatible modem usually pays for itself within a few months.
Why CenturyLink modems are different from cable modems
Here is the short version: cable internet lets you use almost any DOCSIS modem, but CenturyLink does not. CenturyLink delivers internet over two networks, and each needs a matching gateway. A gateway is an all-in-one modem and Wi-Fi router in a single box. DSL service runs over copper phone lines. Quantum Fiber, CenturyLink's fiber brand, runs over fiber-optic cable and is available in most metro markets across CenturyLink's 16-state footprint.
A modem built for one network will not work on the other, and a modem built for a slower DSL tier will not unlock a faster plan. Every modem in this guide is on CenturyLink's certified list, meaning it has been tested on the network to connect and run at its rated speed.
How do I find my CenturyLink speed tier?
Check your plan name in your My CenturyLink account or on your bill. CenturyLink sells three main tiers, and the name tells you what you need:
- Simply Unlimited Internet (DSL): up to 100 to 140 Mbps over phone lines, in areas without fiber.
- Quantum Fiber 500 Mbps: symmetrical fiber, meaning your upload speed matches your download speed.
- Quantum Fiber 940 Mbps (1 Gig): the fastest mainstream tier, with 2 Gig and higher offered in select areas.
Not sure if you have DSL or fiber? If CenturyLink ran a new cable to your home and your plan lists matching upload and download speeds, you have fiber. If your modem plugs into a phone jack, you have DSL.
CenturyLink compatible modems by speed tier
Best modem for CenturyLink DSL up to 100 Mbps (single line)
For most DSL plans up to 100 Mbps, the GreenWave C4000LG or its Zyxel-built twin, the C4000LZ, are the best choice. Both add Wi-Fi 6 for better range and more simultaneous devices, and both handle every standard DSL profile up to 100 Mbps over a single phone line. On a tighter budget, the Zyxel C1100Z is a proven, lower-cost unit that covers the same single-line plans with basic dual-band Wi-Fi. Older single-line options like the Technicolor C1100T also work for legacy ADSL and lower-speed VDSL connections.
Best modem for CenturyLink DSL up to 140 Mbps (bonded)
If your plan reaches up to 140 Mbps, you likely have a bonded connection, which combines two phone lines for extra speed. You need a bonded modem to use it. The Zyxel C3000Z is the standout here: it bonds two VDSL2 lines, supports the faster 35b profile, and includes strong AC2200 dual-band Wi-Fi. The Actiontec C3000A is a close equivalent, and the Actiontec C1900A is a solid bonded option for HD streaming and gaming households. A single-line modem will cap your speed on these plans, so bonding support is the feature to look for.
Best modem for Quantum Fiber 500 Mbps and 940 Mbps
For Quantum Fiber, you need a fiber gateway, not a DSL modem. The two best picks are the GreenWave C4000XG and the Zyxel C3510XZ. Both are Wi-Fi 6 gigabit gateways that comfortably handle the 500 Mbps and 940 Mbps (1 Gig) tiers. The C4000XG has a clean, antenna-free design tuned for fiber, while the C3510XZ offers higher-rated AX5700 Wi-Fi for busy homes with many devices. Either one lets you run a full gigabit plan without leasing CenturyLink's gateway. The Technicolor C2100T is another dual-band gateway that supports both fiber and VDSL2 if you want a flexible option.
What about Quantum Fiber 2 Gig and faster?
Multi-gig Quantum Fiber plans (2 Gig, 3 Gig, and up to 8 Gig in select areas) move past what these gigabit gateways can deliver. For those tiers, CenturyLink installs its own multi-gig fiber equipment, and you would pair it with a multi-gig Wi-Fi 6E or Wi-Fi 7 router. If you are on a standard plan up to 1 Gig, the fiber gateways above are all you need.
| Modem | Best for (speed tier) | Wi-Fi | Top supported speed | Price |
|---|---|---|---|---|
| Zyxel C1100Z | DSL up to 100 Mbps (budget, single line) | Dual-band 802.11n | About 100 Mbps DSL | Check price |
| GreenWave C4000LG / C4000LZ | DSL up to 100 Mbps (single line, Wi-Fi 6) | Wi-Fi 6 (802.11ax) | About 100 Mbps DSL | Check price |
| Zyxel C3000Z | Bonded DSL up to 140 Mbps (two phone lines) | Wi-Fi 5 (AC2200) | About 140 Mbps DSL | Check price |
| Zyxel C3510XZ | Quantum Fiber up to 1 Gig (busy homes) | Wi-Fi 6 (AX5700) | 940 Mbps fiber | Check price |
| GreenWave C4000XG | Quantum Fiber up to 1 Gig (fiber-optimized) | Wi-Fi 6 (802.11ax) | 940 Mbps fiber | Check price |
Speeds shown are the wired maximum each modem is matched to. Actual speed depends on your plan, wiring, and distance from the network. See every certified option in our CenturyLink modem collection.
How much does buying your own CenturyLink modem save?
On DSL plans, CenturyLink charges about $15 a month to lease a modem. That is roughly $180 per year, every year, for hardware you never own. A compatible refurbished modem usually costs far less and pays for itself within a few months, then keeps saving you money for as long as you use it. You also avoid the non-return fees that apply if a leased modem is lost or sent back late.
How do I set up and activate a CenturyLink modem?
Activation takes about 15 minutes and does not require a technician for most modems. Here is the simple version:
- Plug in the modem. For DSL, connect the green phone cord from your wall jack to the DSL port. For fiber, connect the fiber line to the gateway. Then add power.
- Wait for the lights. Give it up to 15 minutes to boot and update. A solid blue or green light means it reached the network. A solid red light means it is not connected yet.
- Activate online. Connect a computer or phone, open a browser, and go to connect.centurylink.com, or use the My CenturyLink app. Follow the prompts to verify your account and accept the terms.
- Set your Wi-Fi. Choose a network name and a strong password. The default login is printed on the modem's sticker.
If you are reusing a modem from another line, do a factory reset before you start so it can connect cleanly on your account.
CenturyLink modem FAQ
What modems are compatible with CenturyLink?
CenturyLink works only with modems on its certified list. Common compatible models include the Zyxel C1100Z, C3000Z, and C3510XZ; the GreenWave C4000LG, C4000LZ, and C4000XG; the Actiontec C3000A and C1900A; and the Technicolor C1100T and C2100T. You can see the full lineup in one place in our CenturyLink modem collection.
Can I use my own modem with CenturyLink or Quantum Fiber?
Yes, as long as the modem is CenturyLink certified and matches your service type and speed. CenturyLink does not allow generic third-party DSL modems the way cable providers accept any DOCSIS modem, so the unit must be on the approved list. Once it is connected to an active line and activated, it provisions automatically.
What is the best modem for CenturyLink DSL?
For single-line DSL up to 100 Mbps, the GreenWave C4000LG with Wi-Fi 6 is the top pick, with the Zyxel C1100Z as a budget choice. For bonded DSL up to 140 Mbps, choose the Zyxel C3000Z, which bonds two lines for full speed.
What is the best modem for Quantum Fiber?
The GreenWave C4000XG and Zyxel C3510XZ are the best Quantum Fiber gateways for plans up to 1 Gig. Both are Wi-Fi 6 and handle the 500 Mbps and 940 Mbps tiers with room to spare.
Do I need a different modem for fiber and DSL?
Yes. DSL modems and fiber gateways are not interchangeable. A DSL modem connects to a phone line, while a fiber gateway connects to the fiber line. If you switch from DSL to Quantum Fiber, you will need a fiber-capable gateway like the C4000XG or C3510XZ.
How do I avoid the CenturyLink modem rental fee?
Buy a compatible modem instead of leasing one. CenturyLink's DSL modem lease runs about $15 a month, so owning your modem removes that charge entirely. If you currently lease, return the leased unit after your own modem is active to stop the fee.
Will the Zyxel C3000Z work on a gigabit plan?
The C3000Z can technically support fiber, but CenturyLink now recommends a dedicated fiber gateway for gigabit plans. For a 940 Mbps Quantum Fiber connection, the GreenWave C4000XG or Zyxel C3510XZ is the better, fully supported choice. The C3000Z is best used for bonded DSL up to 140 Mbps.
