Zyxel C4000BZ Bonded DSL WiFi 6 Modem Router | CenturyLink, Brightspeed

The Zyxel C4000BZ is a bonded DSL modem and WiFi 6 router in one unit, built for CenturyLink and Brightspeed internet service. Bonded DSL uses two phone lines together to carry more speed than one line can. CenturyLink lists the C4000BZ among its recommended modems, and Brightspeed lists it as a certified modem.

Quick Specs

Built for Two-Line (Bonded) DSL

The C4000BZ is the bonded line model in the Zyxel C4000 series. A bonded plan runs over two phone lines at once, and the modem combines them into one faster connection. CenturyLink has tested the C4000BZ at up to 140 Mbps on bonded VDSL2. The speed you get depends on your plan and the condition of your lines.

If your service uses one line, choose a single-line model instead, such as the C4000LG or the C4000LZ. Your provider can tell you whether your plan is bonded.

Dual-Band WiFi 6 Built In

The C4000BZ has a dual-band WiFi 6 router built in, so one box handles both the DSL connection and your home WiFi. It supports 160 MHz channels on 5 GHz for speeds up to 2.4 Gbps between the modem and WiFi 6 devices, and it works with older WiFi devices too. WPA3 security and a separate guest network are included.

For a large or multi-story home, add a mesh network system to one of the Ethernet ports.

Five Gigabit Ethernet Ports

Four Gigabit LAN ports connect wired devices such as a desktop computer, game console, smart TV, or network switch. A fifth Gigabit port works as either a WAN or a LAN port.

C4000BZ vs C4000BG

Both are bonded-line C4000 modems with WiFi 6, and CenturyLink recommends both. The C4000BZ is made by Zyxel. The C4000BG is sold under the Greenwave and Axon names. Either one fits a two-line CenturyLink or Brightspeed plan.

Provider Compatibility

• CenturyLink: on CenturyLink's recommended modem list for bonded DSL.
• Brightspeed: on Brightspeed's certified modem list as part of the C4000 series.
• Fiber service: CenturyLink does not list the C4000BZ for fiber. For CenturyLink Fiber, see the C4000XG.
• Cable internet: not compatible. This is a DSL modem.

Call your provider before you order to confirm the C4000BZ fits your plan and line type. You can also browse all CenturyLink compatible modems and Brightspeed compatible modems.

Frequently Asked Questions

Does the Zyxel C4000BZ work with CenturyLink?

Yes. CenturyLink lists the C4000BZ among its recommended modems for bonded DSL service.

Does the Zyxel C4000BZ work with Brightspeed?

Yes. Brightspeed lists the C4000BZ as a certified modem in its C4000 series.

Is the C4000BZ for bonded or single-line DSL?

It is a bonded line modem, made for plans that use two phone lines. For single-line service, choose the C4000LG or C4000LZ.

Does the C4000BZ have WiFi 6?

Yes. It has dual-band WiFi 6 with speeds up to 600 Mbps on 2.4 GHz and up to 2.4 Gbps on 5 GHz.

How fast is the Zyxel C4000BZ?

CenturyLink has tested it at up to 140 Mbps on bonded VDSL2 and up to 40 Mbps on bonded ADSL. Your speed depends on your plan and your lines.

Does the C4000BZ work with cable internet?

No. It is a DSL modem and does not connect to a cable (coax) line.