How to Hook Up a Comcast Cable Box

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Written by Jack Lloyd

Last Updated: September 23, 2024 Fact Checked

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Preparing Your TV

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Connecting the Box

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FAQ

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Video

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Tips

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Warnings

Do you need to set up a brand new Xfinity cable box? Prepare your TV by putting the box nearby. Connect the HDMI cable to the TV and cable box, and attach the coaxial cable to the box. Once turned on, call Comcast to activate it. This wikiHow teaches you how to connect a Comcast cable box to your TV.

Setting Up an Xfinity Cable Box

To hook up a new Comcast cable box, make sure the box is in a good position near the TV. Connect the coaxial cable to the box, and then connect an HDMI cable to the box and TV. Once connected and on, call Xfinity to activate it officially.

For popular FAQs on hooking up a Comcast cable box, jump to more common questions.

Part 1

Part 1 of 2:

Preparing Your TV

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1
Make sure that you have cable installed. If a Comcast representative didn't come to your house to install cable, you'll need to call Comcast and request the installation.
- If you call Comcast, be sure to have your account information and ID on-hand.
2
Confirm that you have the correct cables. If your TV is an HDTV, you can use an HDMI cable to connect your Comcast box to your TV; if not, you'll need standard A/V cables (the red, yellow, and white cables) to connect the box to your TV.^{[1]
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- The cable box should come with A/V cables.
- You can usually buy HDMI cables for under $15 online or in a tech store.
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3
Turn off and unplug your TV. Press your TV's "Power" button (or the "Power" button on the TV's remote), then remove the plug from the back of the TV.
- Leave the TV's power cable plugged into the wall during the setup process.
You'll need plenty of space to hook up the cable box, so move your TV and/or entertainment center a foot or two away from the wall. This should give you enough room to attach the cable box without bending any wires.
It's good to have a general idea of where the cable box will go before you start plugging in wires, so make sure the box is roughly where you want it before continuing.
You should see several slots and connectors in the back; this is where you'll plug in all of the necessary cables. You can now proceed to connecting the cable box to your cable service and TV.

Part 2

Part 2 of 2:

Connecting the Box

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1
Attach the Comcast coaxial cable to the box. Find the cable that Comcast installed—it will usually be sticking out of the floor or the wall behind your TV—and plug it into the metal coaxial input in the back of the cable box, then screw the connector clockwise to tighten it.^{[2]
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- The cable's end has an attachment resembling a needle in the middle of it.
- Your cable box should have a coaxial cable included. If Comcast didn't install a cable for you, you can attach the other end of this cable to the coaxial input in the wall.
2
Plug in one end of the HDMI cable. It goes in the wide, narrow port in the back of the cable box. On most Comcast cable boxes, the HDMI port is either in the bottom-right corner of the box or at the bottom of the box's back.^{[3]
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- If you're using A/V cables instead, plug each cable into the same-colored port on the back of the box (e.g., plug the yellow cable into the yellow input).
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Plug the other end of the HDMI cable into the TV. Find your preferred HDMI port on your TV, then attach the cable box to the port in question.^{[4]
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- If you have a receiver with multiple HDMI ports plugged into your TV, you can plug your cable box's HDMI cable into the receiver instead.
- If you're using A/V cables instead, plug the cables into the same-colored ports on the back of your TV.
Plug the power cable into a wall outlet or power strip. You should choose a power outlet close enough to the TV that you'll be able to place the box near the TV without stretching or bending any wires.^{[5]
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Plug the other end of the power cable into the cable box. You should see a circular power input on the back of the cable box; fit the end of the power cable into this input.^{[6]
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- This input is normally on the right-hand side of the box.
Doing so will also turn on your Comcast cable box, though you may have to wait several minutes before the box is fully on.
Press the "Input" or "Source" button on your TV or remote to switch to the input (e.g., HDMI 1) into which you plugged your Comcast box.^{[7]
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Set up your Comcast remote. Insert the batteries into your remote, then proceed with connecting it to your TV and cable box.^{[8]
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- Cable box and remote instructions vary from model to model, so consult your remote's manual for instructions on synchronizing the remote with your TV and cable box.
Activate your cable box. Once your cable box has been connected, all that's left to do is activate the service. To start this process, you can call Comcast at 1-855-652-3446, or you can go to the activation website at xfinity.com/activate and sign in.^{[9]
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Common Questions: Troubleshooting Your Cable Box

Why isn't my cable box connecting to my TV?

If your cable box isn't connecting to your TV, make sure the coaxial cable is properly wired through your house. Additionally, make sure the HDMI cable is in the correct port on both the TV and box. If needed, try a newer HDMI cable.

Do I need Wi-Fi to set up my Xfinity cable box?

You will need to connect your cable box to Wi-Fi to finish the set up process. This is how you'll get the newest updates on your device.

Why does my TV have no sound?

Make sure your TV is set to the correct audio output. If you have external speakers connected, check that they're plugged into the TV correctly.

Video

Tips

Using a power strip (also known as a "surge protector") behind your TV will allow you to organize your power sources without straining any wires.

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