One of those things that irks me about the FCC regulations is that manufacturers are responsible for preventing, and can apparently be held liable for, end-user modifications to wireless radio devices under 47 CFR Part 15, Subpart C:

  • 47 CFR § 15.203:

    An intentional radiator shall be designed to ensure that no antenna other than that furnished by the responsible party shall be used with the device. The use of a permanently attached antenna or of an antenna that uses a unique coupling to the intentional radiator shall be considered sufficient to comply with the provisions of this section. The manufacturer may design the unit so that a broken antenna can be replaced by the user, but the use of a standard antenna jack or electrical connector is prohibited. [...]

  • 47 CFR § 15.212(a)(2)(iv):

    Manufacturers must ensure that only transmitter control elements and radio front end components that have been approved together are capable of operating together. The transmitter module must not operate unless it has verified that the installed transmitter control elements and radio front end have been authorized together. Manufacturers may use means including, but not limited to, coding in hardware and electronic signatures in software to meet these requirements, and must describe the methods in their application for equipment authorization.

As a result, manufacturers are forced to actively design wireless radio devices to prevent unauthorized end-user modifications:

  • The RP-TNC connector used for Wi-Fi antennas was originally meant to be a nonstandard connector to prevent consumers from replacing antennas with those not approved by the manufacturer. The connector ultimately gained widespread use; however, the FCC has not taken action against device manufacturers.
  • Major laptop manufacturers, including Dell, HP, and Lenovo, restrict the specific Wi-Fi cards which may be installed into a particular system through the use of "whitelists" in system firmware that specify which card models are allowed. If a Wi-Fi card that isn't on the whitelist is installed, the system will not boot.

Why hold the manufacturer responsible for preventing end-users from making modifications? What is the philosophy or historical basis for these rules? (To prevent this question from being too opinion-based, I'd like to see answers that cite relevant documentation such as rulemaking reports.)

  • I don't see language in 47 CFR Part 15 making manufacturers liable for modifications made by end users. What text supports your premise that this liability exists? Aug 1, 2020 at 14:48
  • Overhauled the question, adding relevant legal citations. It's tempting to rant about regulatory overreach especially where it involves making private-sector actors responsible for enforcing regulations against consumers, but ultimately took it out of the question after several revisions.
    – bwDraco
    Aug 1, 2020 at 15:13
  • No references, thus just a comment. You don't want to make it too easy for a clueless end user to accidentially build something that violates code. End users don't know, and generally have no way to find out, how much interference their setup causes. If it was possible to connect some ubiquituos antenna to some wifi transmitter, extending the range by 3 but causing a tremenduous amount of interference, lots of innocent people would independently do so. Aug 1, 2020 at 16:43
  • Sure, you can crack down on people and fine them, but most of them wouldn't be "evil", and FCC's mission is not "make as many people as possible break the rules to collect as many fines as possible", but "make people obey the rules"; telling manufacturers to make it hard, for customers, to break the rules, seems like a sensible approach. Aug 1, 2020 at 16:45
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    I’m voting to close this question because questions about why the law says something are off-topic here. Law.SE is for questions about what the law is. However you might do better over on Politics.SE, where this is squarely on-topic. Aug 1, 2020 at 17:07

2 Answers 2


It is practically impossible to effectively enforce the radio regulations on every individual user, so it is necessary to have device manufacturers act as gatekeepers.

Had the law been written to rely solely on enforcement against end users rather than manufacturers, its effectiveness would be severely degraded and we'd end up with extremely polluted radio frequency spectrum. Heck, I'd be surprised if Wi-Fi, LTE, or any other consumer radio service worked to any meaningful degree if the law isn't designed the way it currently is.

The FCC relies heavily on user complaints for enforcement. Absent manufacturer restrictions, there would realistically be tens to hundreds of thousands of noncompliant users collectively spewing insane amounts of RF interference. In this scenario, the FCC would be swamped with user complaints, and would essentially need to monitor the entire radio frequency spectrum across the entire nation to have any significant chance of achieving a high degree of compliance. Obviously, the FCC, like any government agency, has limited resources so this is not a realistic possibility, not to mention that this kind of monitoring would create significant privacy risks.

By requiring manufacturers to enforce radio restrictions against users, the potential for users to generate harmful interference is greatly reduced, and the FCC can focus on enforcing the rules against the small number of manufacturers that fail to implement such restrictions.


Because by doing so they force the manufacturers to make the anti-tampering efforts you describe

In the absence of such liability, manufacturers would use standard components that make it trivially easy to make modifications. Regulators don’t want that because user modifications are less likely to comply with RF law.

The radio frequency spectrum is a limited natural resource which is very vital and strategic in the operation of telecomunications. Considering that the radio frequency spectrum is a limited natural resources, its management is regulated internatioanlly by the International Telecomunication Union (ITU), in which details are set out in the radio regulations (RR) as an integal part of the ITU Convention.

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