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Signal boosters are discontinued and no longer available for purchase. If you want help with signal booster setup or connection issues, we have you covered.

Set up a signal booster

Get to know your signal booster

The device includes a window unit, which receives T-Mobile signal (minimum of 1 bar 3G, 4G, or 4G LTE), and a separate coverage unit, which rebroadcasts the signal in your home.

Window unit

  • Receives T-Mobile 3G, 4G, or 4G LTE signal from outside, and sends it to the coverage unit.
  • Place this in a well-ventilated area with the strongest and most reliable 4G LTE signal. This is usually best in a window.

    Bars of signal indicator on the 4G LTE Signal Booster Window Unit.

Coverage unit

  • Rebroadcasts T-Mobile's signal throughout the home, boosting your signal strength and reliability.
  • Place this in a well-ventilated area to provide the best in-home coverage.

Set up your signal booster service

Setup usually just takes 15 minutes. When a new channel is added to the network but not included in the signal booster, device setup time may take up to one hour instead, while the device updates. Review the steps to set up your signal booster.

  1. Connect your CellSpot to the Internet. Use the yellow Ethernet cable from the β€œWAN” yellow port on your CellSpot to an available Ethernet port on your Wi-Fi router or Wi-Fi cable modem router.
  2. Connect the GPS antenna cable to the GPS port. Position the antenna as close to a window as possible.
  3. Connect the power cable to the CellSpot power port, then plug in your AC power adaptor into the power outlet.
  4. Let your CellSpot set up. After you power on your CellSpot, the CellSpot will go through a self-installation process. During this process, the power LED will be in flashing green as the device downloads the latest software and performs device location verification. It can take up to 2 hours to complete the device setup.


Register or update your signal booster location

If you just received a signal booster from T-Mobile's loaner program, it's already set up for the address where it was delivered. No need to register!

If you moved to a new address or bought a non-T-Mobile signal booster, visit Register a signal booster.


Troubleshoot issues with your signal booster

Read me first

  • Before following the steps below, ensure the following:
  • Ensure the issue only happens when using the signal booster. Otherwise, follow signal issues on device.
  • Check for an indicator light.
  • Follow the setup video above for best results.
  • Make sure the device is in a 3G / 4G coverage area. If not, your location doesn't have any signal to boost.
  • Unplug the power adapter from both units, wait a few minutes and then plug them in.
  • Test your phone without LTE enabled.
  • If your device meets the criteria above, but the issue persists, proceed with the steps below.


Window unit errors


No lights, Power light is off

  1. Verify power supply is plugged into the Window Unit and wall outlet correctly.
  2. Verify there is power to the outlet by testing with another electrical device.
  3. Swap the power supply with the coverage unit to check if the power supply is defective.

No bars of signal

  1. Place window unit in a location that receives 3G/4G coverage.
  2. Check the signal level on the handset (may take 1-2 minutes) where the window unit is placed.
  3. The handset should show 1 solid bar of signal where the window unit is located.
  4. Check the status light on the window unit. If it is flashing red or solid red, refer to those error steps.

Flashing green

  1. Wait for the light to stop flashing green.
  2. Ensure window and coverage units are not placed close to a 5 GHz cordless phone, wireless router, or Wi-Fi device.
  3. This helps prevent in-home interference, which can impact the size of the coverage bubble and signal strength.

Flashing red

  1. Verify a connection has been established. The status light blinks or flashes red when scanning.
  2. Once connection is established, the status light turns off and the power light remains solid red.
  3. Verify window unit vents are not blocked or covered.
  4. Move window unit to a cooler spot.
  5. Wait a few minutes and check if the window unit works and if the flashing red status light has gone away.

Solid red

  1. Unplug the window unit power cord.
  2. Wait 10 seconds.
  3. Plug the window unit power cord in.

Error 2

  1. Attempt to place a call.
  2. If you cannot place a call or use data, move window unit to a different location.

Error 4

  1. Clear window unit vents of any blockage. Ensure location of unit allows free flow of air.
  2. Once the window unit has cooled down, it will operate as normal.

Error 6


Unplug the window unit for a few seconds and then plug it back in.


Error 8

  1. Move window unit to another location.
  2. You might need to move your system to the other side of your home.
  3. When you have an E8, your system will still offer you indoor cellular coverage.


Coverage unit errors


Error 0, Too close

  1. Unplug the coverage unit.
  2. Move coverage unit farther away from window unit.
  3. Plug coverage unit in.

Error 1, Error 5

  1. Ensure signal booster is being used at the primary use address.
  2. Move coverage unit to a location where you have better cell phone coverage.
  3. Confirm this location's signal strength using the your mobile phone.
  4. If the mobile phone cannot get signal, the signal booster will not work.

Error 2

  1. Attempt to place a call.
  2. If you cannot place a call or use data, move window unit to a different location.

Error 3, Error 4, or Flashing red

  1. Check the coverage unit vents are clear, and they have free airflow.
  2. Move coverage unit to a cooler spot.
  3. Once your coverage unit has cooled down, it will operate as normal.

Error 7

  1. Move the device and verify if it works. If it works, it may be Error 1 that looks like an Error 7. If so, follow Error 1 steps above.
  2. Restart the coverage and window units.

Error 8

  1. Move coverage unit to another location.
  2. Repeat until you no longer get Error 8.

Flashing green

  1. Wait for the status light on the coverage unit to stop flashing green.
  2. This may take up to 10 minutes.

Low coverage

  1. Move the coverage unit farther away from the window unit.
  2. The coverage indicator value increases as the coverage area increases.

Poor coverage

  1. Determine how many signal bars you have on the phone vs. the coverage unit. The more bars shown on the window unit the better the coverage will be.
  2. Move window unit to an area that has better 3G/4G coverage.
  3. To increase the coverage area, move the coverage unit farther away from the window unit; the higher the coverage indicator value, the better the coverage. A 6 is the minimum supported coverage value.
  4. If you are using a wireless data device such as a baby monitor, cordless phone, or Wi-Fi router, the coverage unit should be positioned at least three feet away from the device. Placing it too close can degrade data rates or even make it impossible to connect.

Power light is off

  1. Verify power supply is properly connected to coverage unit and power outlet.
  2. Verify outlet has power.
  3. Swap power supply with the window unit to verify if the power supply is defective.

Solid red

  1. Unplug the coverage unit.
  2. Wat at least 10 seconds.
  3. Plug the coverage unit back in.
  4. Check if there are any error code messages.
    • If there are error codes, follow the steps for appropriate error code.
    • If there are no error codes, contact us.

Too far

  1. Units may take five to ten minutes to re-establish connections.
  2. If issue persists, verify both units have same serial number.
  3. Locate the serial number is located on the bottom of the units on the manufacturer label.

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