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Comment by utensil4778 | Hacker News Reader

The usual line that Lenovo gives is that this is for FCC reasons. The argument goes that the laptop is FCC certified as an entire unit, and changing the WiFi card technically invalidates this.

This is quite plainly nonsense. Every other manufacturer allows WiFi adapter replacements because every module on the market must be individually FCC certified.

Technically, the claim does make sense under a creative interpretation of the FCC rules. I think the real reason is likely so you'll buy replacement FRUs from Lenovo under your enterprise support contract, as well as ensuring you use a module that is known to work reliably with the software stack shipped on the machine.

Basically yeah, its an anticompetitive measure.

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> This is quite plainly nonsense. Every other manufacturer allows WiFi adapter replacements because every module on the market must be individually FCC certified.

Perhaps every other OEM are running antennas through the case that have exactly the gain you'd expect on the bands you'd expect; while Lenovo are using better-than-average antenna designs together with lower signal amplification to achieve the same SNR with lower total power consumption.

If that's the case, then swapping out the wi-fi card for one that hasn't been programmed for below-standard signal amplification, will get you a system that's above the FCC limits.

If that sounds silly, while working in commercial construction in Los Angeles, we encountered pushback for placing UL-listed devices in a UL-listed enclosure. The city determined that to be a “new assembly” and required UL listing for the entire unit. UL has a category for this situation; the enclosure is “UL recognized” because all of the devices and the enclosure are UL-listed. Their proposed solution, which UL was happy to oblige, was to come and field-inspect the installed units and have them certified in situ, at our (significant) expense, of course.

TBH that doesn't sound ridiculous at all. "UL recognized" is not the same thing as "UL listed."

The former means that the assembly is assumed to meet UL specifications; the second means that it has been inspected by UL and confirmed that the assembly actually does meet specifications.

Making sure that things meet specifications is the entire point of the building department's inspections.

I acknowledged that in my comment. Part of my point here is that UL is not exactly a disinterested 3rd-party when it comes to endorsing additional layers of certification.

I assume you know this, but depending on what the enclosure was made of, what frequencies the devices inside were broadcasting at, and where you placed them inside, you could very well have accidentally produced a resonating chamber, parabolic antenna emitter, or other type of structural frequency-specific gain-boosting mechanism.

They likely wanted to just make sure that you hadn't done that. (And to do that, they had to send some fellows whose time was very expensive, because it takes long experience to build up an intuition for these things to the point that you're confident enough in your answer to not have to bother with the "measure everything and plug-and-chug the dynamics in a simulator" step.)

In this particular case, it was a guest room control solution consisting of DIN rail mounted TRIAC dimmers 0-10V dimmers and other line-voltage & dry contact relays. Backbone was an RS485, 4-conductor bus. Yes, those components can produce various harmonica and frequencies, however they were tested extensively in a lab in various configurations. Each configuration varies slightly based on room layouts and number of zones, and obtaining UL-listing for every possible permutation becomes ridiculous (IMO).

at our (significant) expense, of course.

When I see situations like this, it's often because someone on the other side, or someone related, benefits from the arrangement. They would never admit so, but that's how things tend to turn out like that.

> This is quite plainly nonsense.

Unfortunately, Lenovo is actually correct in how the laws are written.

Whether or not they would get in trouble for it is a different question. I wouldn’t be surprised if they were put on notice for something 20 years ago by an over eager FCC person and they took the lesson to heart. Once a company gets threatened for something they rarely go back, even if other companies are getting away with it.

Other manufacturers such as Dell and HP do in fact implement BIOS whitelist. I think this is the reason why Internet listings of Wi-Fi cards are advertised with brand names that the cards are intended for.

The slot in question is not a slot for a part 15 WiFi card. It's a slot for a cellular modem, complete with pins going to a SIM slot. There's FCC complications with that that go beyond the standard part 15 rules. You're also dealing with carrier certifications—yes, carriers want your precise M.2 cellular modem, laptop, and antenna configuration tested before they allow your device on the network. (In practice you can get away with not doing this, although some carriers are making moves to eventually disallow devices whose TACs can't be tied to a carrier certification.)

Eh? I didn't know that only one singular slot was in question here, or that the conversation had shifted from talking about WiFi to instead talking about cellular.

My own ThinkPad absolutely has independent slots for WiFi and cellular cards, and they look similar but they aren't even electrically compatible. (One is a mini PCIe with PCI Express and without USB, and the other is mini PCIe with USB and without PCI Express.)

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