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Comment by chedabob

5 months ago

Yeah there was this the other day, although I'd expect the hardware for this is much smaller than is shown in the photos in the OP: https://news.ycombinator.com/item?id=45294766

Nah it's that size. You need an individual modem for each SIM card because you need a unique IMEI. It's possible each of those SIMs are eUICCs as well which means basically that each card is like a "wallet" with multiple profiles.

I've used hardware a decent amount larger than what's pictured in the OP for work. But what I was using wasn't just for SMS. So I needed more sophisticated modems. What they're using looks like a bunch of 64 port modem banks exclusively for SMS.

(Oh wait if you mean the devices for what's in the article you linked, then yea, those I'm sure are much smaller and quite different.)

  • What kinds of things do these devices get used for in legit enterprises? If you're able to say :-)

    • I used to send a lot of SMS verification codes. We considered setting up a SIM box, but never did. You get different SMS routing from a phone on a major network than you do from the SMS aggregators, and that could be useful for getting codes to difficult destinations.

      But we had enough volume that we could typically get improvements on routing by asking aggregators about difficult destinations (unless the difficulty was coming intentionally from the destination carrier). The aggregators do sometimes use grey routes from SIM farms. Squishyness around terms of use and accounting would have been an issue too, we would not have been able to fly under the radar on 'unlimited messaging'

      Another potential use could be if you needed to send a lot of alerts to your employees/customers in a short period. Most aggregators have rate limits, and so do carriers... if you're a big customer, you can probably get limits raised; if you only have an occasional need, you might prefer to have a large number of low cost SIMs.

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  • The modems don’t support on-the-fly IMEI programming? Even if not, I could see the same RF components share a number of whatever the bare minimum chip is for an IMEI and switch

    • I would just get a decent SDR like xtrx and some derivative of osmocom stack and then it's two antennas and however many sims you want. But.. this info is outdated, this stuff was available five years ago.

    • They seem to do some multiplexing of the antennas at least. Counting from the pictures I see 16x16=256 SIM cards and 4x4x4=64 antennas.