I'm not sure this is the right section, I apologize in advance. I'm from Italy, we recently had some issue using an italian SIM card (only-data SIM card, provider is WIND Tre) which is supposed to work off the shelf in roaming with AT&T in US. We used an industrial professional router (Digi IX20) and everything was working here in Italy, but then in US we got "No signal" and weren't able to use that at all. Router manufacturer claims that in order to work with US networks, the device IMEI has to be registered.. is that true? Why this don't apply to phones? Who take care of this registration?


Router model is specifically this and roaming is enabled.

  • 4
    You need to ask AT&T, not random people on the internet. May 17, 2021 at 16:23
  • 3
    On phones, data roaming usually defaults to disabled. Just to make sure: It is enabled on your router, right? // There’s also the thing with different bands, did you verify the router supports all the band AT&T uses?
    – Daniel B
    May 17, 2021 at 16:33
  • @DanielB Yes, I think you're spot on. The OP's router may work in some US regions, not all. Really not recommended. May 17, 2021 at 17:01
  • Editing my question, btw roaming is enabled and I have the global version, which is supposed to work in US too out of the shelf.
    – rok
    May 18, 2021 at 7:18

1 Answer 1


According to AT&T support their network supports the following LTE bands:

  • 700 MHz: Bands 12/17/29
  • 850 MHz: Band 5
  • 1900 MHz: Band 2
  • 1700 MHz/2100 MHz: Bands 4/66
  • 2300 MHz: Band 30

The Digi IX20 specifications page shows there are different variants and none supports all AT&T bands. It'll depends on the specific coverage in the region you're trying to use the router. Where the coverage is mainly 1700/2100MHz the the "M1" variant may work but without 3G fallback. For the 700MHz regions the "G4" and "N4" may work on one band only and dependent on availability and signal strength.

You need to contact AT&T and check which bands are available in the region you're trying to use the router.

EDIT: A special thanks to @DanielB for pointing out the right direction.

  • 1
    Reasonable answer, I'm surprised they support euro roaming at all. +1 May 17, 2021 at 18:34
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    @Tim_Stewart Not long ago the service was bad, coverage was deficient and roaming was very expensive. But now you can travel from Germany to Portugal with good coverage, quality and 4G almost everywhere and roaming, both voice and data, is only cents more expensive than your own network at home. The 5G coverage is only second to China (thanks Huawei!) but yes, still a distant second. May 17, 2021 at 19:59
  • Thanks for the clear answer. I have specifically this link and looking at the bands, there are some missing compared with AT&T support.. so probably that's the reason. What about the IMEI registration.. is that an issue ?
    – rok
    May 18, 2021 at 7:17
  • I don't think registration is necessary but it's a question better answered by AT&T. May 18, 2021 at 20:30

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