Repair: ‘US/DS Light Blinking’ on Xfinity Internet Connection

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The modem LEDs are a visual indication of the current status. It is normal for your US/DS (upstream/downstream) lights to come on briefly during connection establishment. Flashing or continuous flashing US/DS LEDs indicate that the modem cannot establish a connection due to a defective or missing signal.

The typical reasons for this are:

  • The modem did not work.
  • The wiring has been incorrectly configured.
  • The modem is defective.

The transmitter indicator on a cable modem indicates the status of your uplink. When the transmit indicator is on, there is a fixed uplink connection between you and your ISP. If it flashes constantly without ever being repaired, it means in most cases that there is a failure near you. However, this is not always the case. Sometimes the problem is on your side and you can solve it yourself without calling technical support.

The transmitter indicator on a cable modem indicates your upstream status. If the transmitted light is constant, there is a fixed connection upstream between the residential gateway and the CMTS. If it flashes constantly without ever being repaired, there are a few troubleshooting steps that can be performed.

  1. Remove the coaxial cable from the modem while leaving the unit powered on.
  2. Leave the modem inactive until the reception indicator starts flashing.
  3. Disconnect the modem from the power supply.
  4. Reconnect the coaxial cable to the modem.
  5. Reconnect the modem to the power supply. If this does not solve the problem, call an office representative.

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Resetting the Internet modem

The most basic troubleshooting step you can take to solve this problem is to completely reset the unit due to a power failure. For that:

  1. Disconnect the Internet router from the power socket.
  2. Press and hold the On/Off button on your Internet router.
  3. Reconnect the device and wait for Internet services to start.
  4. Check if the problem persists.

Direct plugging

In some cases, the splitter used to split the Internet cable may be defective and prevent the connection from being established. It is therefore recommended to connect the cable directly to the Internet modem and check if the problem persists. If it disappears, it means that the separator used did not work properly.


On the back of the gateway are four Ethernet adapters (which look like very large telephone jacks) for connecting devices to the Internet that do not have a WiFi adapter or for which you need the fastest and most reliable connection. If you are a powerful player or stream 4K video, it is important to connect via Ethernet. There are no indicators for these cylinders on the front panel.

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