> For the complete documentation index, see [llms.txt](https://help.proxidize.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.proxidize.com/legacy-products/proxy-builder/advanced-configuration/proxidize-modems-bands-and-frequencies.md). # Proxidize Modems: Bands and Frequencies Learn which cellular bands are supported by Proxidize MX2 modems and how to check the bands used by nearby cell towers. ### What Are Cellular Bands and Frequencies? Mobile networks use cellular bands to connect devices to carrier towers. Each band represents a specific frequency range used by a carrier. For example, one carrier may use **LTE Band 3** in one area, while another carrier may use **LTE Band 12** or **Band 20**. When your modem supports the same bands used by nearby towers, it has a better chance of getting a stable connection, stronger signal, and better performance. #### Why This Matters Checking supported bands can help you: * Confirm whether a Proxidize modem is compatible with carriers in your area. * Understand why one SIM or carrier performs better than another. * Choose a better location for your modem setup. * Decide whether band locking may help improve stability or performance. Band support does not guarantee a perfect connection. Signal strength, tower congestion, carrier limits, SIM plan behavior, antenna placement, and indoor coverage can also affect performance. *** ### Supported Bands by Region Proxidize MX2 modems are available in different regional variants. Use the band list that matches your modem region. If you are not sure which modem region you have, contact Proxidize Support before making network or carrier decisions based on this list. #### EU Region MX2 Modem Bands | Network Type | Supported Bands / Frequencies | | ------------ | ----------------------------- | | FDD-LTE | B1, B2, B3, B5, B7, B8, B20 | | TDD-LTE | B38, B40, B41 | | WCDMA / 3G | B1, 2100 MHz; B8, 900 MHz | | GSM / 2G | 850, 900, 1800, 1900 MHz | #### US / North America Region MX2 Modem Bands | Network Type | Supported Bands / Frequencies | | ------------ | -------------------------------------------- | | FDD-LTE | B2, B4, B5, B7, B12, B13, B17, B25, B26, B66 | | TDD-LTE | B41 | | WCDMA / 3G | B2, 1900 MHz; B4, 1700 MHz; B5, 850 MHz | | GSM / 2G | 850, 900, 1800, 1900 MHz | *** ### How to Check Nearby Tower Bands You can use public cell tower mapping tools to check which towers and bands may be available near your location. In this example, we will use [CellMapper](https://www.cellmapper.net/). #### Before You Start * You need to know the approximate location where the modem will be used. * You need to know the carrier or SIM provider you want to check. * Cell tower mapping tools are community-powered, so results may not always be complete or fully up to date. {% stepper %} {% step %} ## Open CellMapper Open [CellMapper](https://www.cellmapper.net/). ![A screenshot that shows the map of Earth centered on eastern Russia.](/files/5f896f690b9352f57f57f6824eb1b11c43796793) {% endstep %} {% step %} ## Search for your location Search for your city, street, or approximate modem location. Use the search option in the map interface to move to the area where your Proxidize modem will be used. ![A screenshot that shows the cell tower map.](/files/933f3330d67f6580a174027108152bb13ab15d31) {% endstep %} {% step %} ## Select the carrier or network provider Choose the mobile network used by your SIM. This helps CellMapper show towers and bands for the correct carrier. {% endstep %} {% step %} ## Click a nearby tower Select a tower close to your modem location. CellMapper should show tower details such as network type, band, frequency, bandwidth, and signal information when available. ![A screenshot that shows the cell tower map of a city.](/files/32086f0bd1d12765b6d6e0bb81190c8a9c562e74) {% endstep %} {% step %} ## Compare the tower bands with your modem's supported bands If the tower uses a band supported by your modem, the modem should be technically compatible with that band. ![A screenshot that shows the cell tower map of a city.](/files/2914fb343761f39f76e3d538b1a5b6b2def4e256) {% endstep %} {% endstepper %} #### Example: If a nearby tower uses LTE Band 3 and you have an EU region MX2 modem, the modem supports that band because B3 is included in the EU FDD-LTE list. If a nearby tower only uses a band that is not listed for your modem region, the modem may not be able to connect to that band. *** ### FDD-LTE vs TDD-LTE FDD-LTE and TDD-LTE are two types of 4G LTE network technology. | Type | How It Works | Simple Explanation | | ------- | ------------------------------------------------------------------------------------------ | --------------------------------------------------------------------- | | FDD-LTE | Uses separate frequency ranges for upload and download traffic. | Upload and download can happen at the same time on separate channels. | | TDD-LTE | Uses the same frequency range for upload and download traffic at different time intervals. | Upload and download take turns using the same channel. | You usually do not need to choose between FDD-LTE and TDD-LTE manually. The modem and network handle this automatically as long as the required band is supported. *** ### When to Consider Band Locking Band locking may help when the modem keeps connecting to a weaker or more congested band even though a better supported band is available nearby. Band locking should be used carefully. Locking the modem to the wrong band can reduce performance or prevent the modem from connecting. For step-by-step instructions, see [USB Modem Band-Locking](broken://pages/da3969a65687ecaa166600cb1640d774d485cfdf). *** ### Troubleshooting | Issue | What to Check | | --------------------------------------------- | ------------------------------------------------------------------------------------------------ | | The modem has weak signal | Check whether nearby towers use bands supported by your modem region. | | The SIM works in a phone but not in the modem | Confirm the carrier uses at least one band supported by the modem. | | CellMapper does not show towers nearby | Try another nearby location, zoom out, or verify the selected carrier. | | Speeds are inconsistent | Tower congestion, signal quality, indoor placement, and carrier throttling can all affect speed. | | Band locking made the connection worse | Remove the band lock or choose another supported band with better signal. | *** ### Related Articles * [USB Modem Band-Locking](broken://pages/da3969a65687ecaa166600cb1640d774d485cfdf) * [How Can I Access My Modem's Web Interface?](broken://pages/924f1a6785b93e99183b482e69ba4d93b7bbdf47) * [Ensuring the Best Endpoint Uptime](broken://pages/bdfbeb853174af5ac2be76168ce9bef90dc69848) ### Need Help? 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