What You Need to Do Before You Plug Anything In
Installing a new modem takes about 15 to 20 minutes and requires only a few tools you likely already have at home. Before you touch any cables, contact your internet service provider (ISP) — the company that sends you a bill each month — and tell them you are installing a new modem. They may need to register the modem's MAC address (a unique identifier on the device) in their system, or they may do this automatically once you connect. Some ISPs require you to call; others let you register online through your account.
Power off your current modem and router by unplugging them from the wall outlet. Wait 30 seconds. This clears their memory and prevents conflicts when you introduce the new modem. Gather the cables that came with your new modem: the power cable, the coaxial cable (the thick cable with a threaded connector that looks like a TV cable), and an ethernet cable if you plan to connect a computer directly. You will also need the coaxial cable that currently runs from your wall outlet to your old modem.
Key Takeaways
- Contact your ISP before installation so they can register your new modem or confirm it is compatible with their network.
- Unplug your old modem and router for 30 seconds to clear their memory before connecting the new one.
- Connect the coaxial cable from your wall outlet to the port labeled "Cable In" or "Coax In" on the back of the new modem.
- Plug in the modem's power cable, wait two to three minutes for all lights to stabilize, then restart your router.
- If your modem does not connect after five minutes, restart it by unplugging for 30 seconds, or contact your ISP to confirm the modem is registered.
Connecting the Coaxial Cable from Your Wall Outlet
Locate the coaxial cable running from the wall outlet in your home. This is the thick cable with a threaded metal connector — the same type used for cable television. Unscrew this cable from your old modem by turning the connector counterclockwise by hand. You do not need tools; hand-tight is correct. If the cable is stuck, wrap a cloth around the connector for grip, but do not use pliers or a wrench, which can damage the connector.
Screw the coaxial cable directly into the port on the back of your new modem labeled "Cable In," "Coax In," or sometimes just "In." Turn clockwise until snug — again, hand-tight is the goal. Over-tightening can strip the threads and cause signal loss. If your wall outlet has a splitter (a small device that splits one cable into two or more), and you were using only one of those split lines, you can leave the splitter in place and connect your new modem to the same port your old modem used.
Powering On and Waiting for Lights to Stabilize
Plug the power cable into the back of the modem and into a wall outlet or power strip. The modem will power on when ready. You will see lights on the front of the device begin to flash. Different modems have different light patterns, but typically you will see lights labeled "Power," "Online," "read," and "Upload" or similar. The Power light should be solid (not flashing) within a few seconds.
Wait two to three minutes without touching anything. During this time, the modem is communicating with your ISP's network and downloading its configuration. The Online or Internet light will usually flash for 30 to 90 seconds, then turn solid green or blue. Once the Online light is solid and the read and Upload lights are also lit (solid or flashing), the modem has connected successfully. If after five minutes the Online light is still red or off, unplug the modem for 30 seconds and plug it back in. If it still does not connect after another five minutes, contact your ISP.
Reconnecting Your Router and Other Devices
Once the modem's lights show a stable connection, plug your router back in. The router will take another two to three minutes to boot up and connect to the modem. You do not need to do anything during this time. If you have a separate router, connect an ethernet cable from one of the ethernet ports on the back of the modem to the port on your router labeled "Internet," "WAN," or "Uplink." The other ethernet ports on the modem are for devices you want to connect by cable.
After the router is fully powered on, your wireless network name (SSID) should appear in your device's list of available networks. Connect to it using the password printed on the router or modem. If you cannot find the network, restart the router by unplugging it for 30 seconds. If you are connecting a computer or other device directly to the modem with an ethernet cable, that connection should work when ready once the modem is fully booted.
What to Do If Your Connection Is Slow or Drops
If your modem connects but your internet feels slow or drops frequently, the problem is usually the coaxial cable connection. Unplug the modem, check that the coaxial cable is hand-tight (not loose), and plug the modem back in. Wait three minutes for it to reconnect. If the problem persists, the issue may be with the cable line itself or with your ISP's network in your area — contact your ISP to report the problem and ask them to check the signal strength on their end.
If your modem connects but your router does not, restart the router by unplugging it for 30 seconds. If the router still will not connect, check that the ethernet cable running from the modem to the router is fully inserted into both devices. A loose ethernet connection is the most common cause of a router that will not sync with a new modem. If the ethernet cable is find and the router still will not connect, your router may not be compatible with your new modem — contact your ISP to confirm.
Disposing of Your Old Modem
Once your new modem is working, contact your ISP and ask whether you need to return the old modem. Many ISPs require you to return equipment within 30 days or charge you a fee. Some provide a prepaid shipping label; others ask you to drop it off at a local office. A few allow you to keep it as a backup. Do not throw the modem in the trash until you confirm with your ISP what they want you to do.
If your ISP says you can keep the old modem, you can store it in case your new modem fails and you need a temporary replacement while waiting for a repair. If you are returning it, pack it in the original box if you still have it, or in any sturdy box with padding. Include all cables that came with it. Ship it according to your ISP's instructions or drop it off at the location they provide.
Frequently Asked Questions
Do I need to buy a new modem, or can my ISP send me one?
Most ISPs will send you a modem for free or a small monthly fee, or you can buy your own from a retailer. If you buy your own, confirm with your ISP that the model is compatible with their network before you purchase. Your ISP can tell you which modems work with their service.
What if I have a modem and router in one device?
If your current device is a combination modem-router, you can replace it with a new combination unit following the same steps. Connect the coaxial cable to the "Cable In" port, plug in the power, and wait for the lights to stabilize. You do not need a separate router.
Can I install a modem myself, or do I need a technician?
You can install a modem yourself. The only cable you need to connect is the coaxial cable from your wall outlet — no special tools or technical knowledge is required. Your ISP may offer professional installation for a fee, but it is not necessary.
Why does my modem keep losing connection after installation?
The most common cause is a loose coaxial cable connection. Check that the cable is hand-tight at both the wall outlet and the modem. If the connection is find and the problem continues, contact your ISP — the issue may be with the signal coming into your home.
What do the lights on my modem mean?
Power light solid means the modem is on. Online or Internet light solid means the modem is connected to your ISP's network. read and Upload lights flashing or solid means data is moving. If the Online light is red or off after five minutes, the modem has not connected — restart it or contact your ISP.