Xfinity Cable Box which has Xfinity as the trade name of Comcast Cable Communications, LLC, is a subsidiary of Comcast Corporation, which used to market consumer cable television, telephone, internet, and wireless services provided by the company.
After receiving a cable TV set-top box from Comcast, it will need to be activated before you can receive channels on it. You can activate your cable box online or by calling Comcast. Newer X1 cable boxes can be activated directly from your TV. Comcast will not activate cable boxes purchased used.
How to Activate Xfinity Cable Box

- Installing the New Cable Box
- Activating the Cable Box
- Troubleshooting

Installing the New Xfinity Cable Box
Connect the “Cable In/RF In” to cable wall outlet. | Use a coaxial cable to make connection. Ensure there is a little slack in the cable There should be no tension on the connectors. |
Connect “HDMI to TV” port on cable box to HDMI port on TV. | Use HDMI cable present in the box or you purchased. Check on HDMI port used for easily switching later. Use HDMI Out port on the box and not Input ports. No HDMI port on TV, use a coax cable to connect the “To TV/RF Out” |
Power On | Plug it in to the Power connector on the back of the box. |
Switch TV to correct input. | Switch to the HDMI input to match port. When using coax cable to connect the box, switch to channel 3 or 4. |
Connect any additional digital adapters. | With multiple TVs and active coax outlets, use digital adapters to connect cable to additional TVs. Each adapter will need its own coax wall outlet. Use a coax cable to attach it to the wall outlet, HDMI /coax cable to connect the adapter to the TV, and then connect the power adapter. |

Activating the Xfinity Cable Box
Turn on the cable box. | With Power button, press it to turn it on. Cable boxes will take up to 20 min to warm up initially. |
Activate on the Comcast website. | The quickest way is to visit the Comcast Activation site. Visit xfinity.com/activate. Enter account number & phone number and wait for activation. |
Activate by calling Comcast. | When online activation service is not working, use phone: Be ready with account number & cable box serial number. For digital adapters, keep the serial numbers for those ready. Call 1-855-OK-BEGIN (1-855-652-3446). Enter the requested numbers whenever prompted, including the telephone number associated with the account and wait for cable box to get activated within 20 minutes. |
Activate using the on-screen menu | While using a newer X1 box then activate using the on-screen menu. Ensure the TV is set to the X1’s input to see X1 startup screen. Select language and wait while the X1 starts up. The initial startup time will take a while to complete for downloading the updates. Enter the information needed to verify account viz., phone number, the last four digits, or the account number. Select a name for X1 box and wait to activate within 20 minutes or so to complete. |

Xfinity Cable Box Troubleshooting
Avoid buying used cable boxes. | When purchased a cable box from eBay, Craigslist, or any re-seller, Comcast will not activate it as it is actually an un-returned rental. Ensure to get cable boxes directly from Comcast for new service, replacements, or additions. |
Check the connections. | A weak connection to wall coax outlet or to the cable box would cause activation issues. Ensure coax cable is tightened at both ends. |
Schedule a service visit. | Bad or old wiring may cause a failure to activate or receive signal. You must call for a Comcast technician to come inspect and fix the lines. If the problem is :- With Comcast equipment = no need to pay With the wiring in home = need to pay if it is rewired. |
Activate equipment quickly. | Comcast recommends activating equipment within seven days of the date of the order. Interference may be caused to the activation while waiting. |
Contact Comcast for error code RDK-03007. | The error code mentioned is related to the account billing, and need to dealt by contacting Comcast to verify the billing information and payment status. |
Hope that you will now, enjoy the services of Xfinity Cable Box without any hassle.