IoT 201: EMC Compliance for IoT Devices

Editor’s note: The challenges of getting your IoT product to market aren’t just technical and managerial. In order to sell your product in most world markets, there are regulatory and compliance issues to consider. This installment of our IoT 101/201 series dives into one of those: Electro-Magnetic Compatibility, or EMC compliance. This post does NOT substitute for the advice of a compliance authority; it is only intended to familiarize you with some of the issues involved.

Electro-Magnetic Compatibility (EMC) is the umbrella term for making sure your IoT device does not interfere with or suffer interference from other electronic devices. All IoT devices emit radio frequency radiation and are therefore subject to a sometimes bewildering array of treaties, laws, and regulations on EMC compliance.

On a practical level, complying with the array of mandates is usually straightforward: we’ve pre-certified ARTIK modules so most product designers just need to print a label referencing our certificates. Even if you need to obtain your own certification you can work with a Certified ARTIK Partner to determine which regulatory body has jurisdiction over the geographic region in which you want to sell your product, find a testing lab the jurisdiction trusts to certify your design, and work with the lab until they sign off on your product.

You’ll have to repeat this process for each regulatory region into which you want to sell, so if you plan to sell globally you’ll need to plan your rollout accordingly. According to the World Bank, the top ten addressable markets around the world each have at least 1 trillion USD annual GDP and collectively account for approximately 67% of global GDP. With only three certifications (US, EU, Canada) you’ll approach 50% of world GDP with two nicely consolidated geographic regions for your supply and distribution chain.

A few definitions

Before I go much further into the discussion of how to get approval for your IoT designs, it’s helpful to define terms.

Engineers and regulators talk about three types of RF-emitting devices:

  • Incidental radiators never intend to generate RF energy but do so anyway. Switches and motors are typical examples.
  • Unintentional radiators deliberately generate RF signals but intend to conduct the energy, not radiate it. Microprocessors and RF receivers are typical examples.
  • Intentional radiators deliberately transmit RF energy. Most IoT designs fall into this category.

Many regulatory bodies make a distinction between:

  • Class A devices which are intended for use only in industrial settings where a single user has control over all RF emitters. It’s the less stringent of the two device classifications.
  • Class B devices are often referred to as “consumer” devices, but from a design point of view it just means you don’t know which other devices will be present in your RF environment.

Regulatory bodies sometimes require different levels of testing and paperwork depending on the classification of the device:

  • Verification allows you to test your own device. It does not require you to file any paperwork but does require you to produce the test reports on request.
  • Declaration of conformity requires testing of your device by an accredited outside testing lab. As in the verification process you do not need to submit paperwork unless requested.
  • Certification is the most rigorous path and it’s the one required for IoT devices. Under certification requirements your design must be tested by an accredited testing lab. The test data and other paperwork are submitted to a separately-authorized body who can issue the certification. Testing labs and authorized bodies are regulated as separate entities, but in practice they’re usually the same company and from now on I’ll just call them “certification labs.”

For the rest of this tutorial I’ll discuss how to comply with regulations for Class B intentional radiators subject to certification.

Choose your path

If your eyes are starting to glaze over and you just want to know what to do, you can skip to the compliance path determined by your product, your market ambition, and your team.

Path

Product

Market

Team experience

Simple

IoT products built with ARTIK modules can use Samsung’s module-level certification to avoid the complexity of certified testing labs, with some caveats discussed below.

Single market (e.g. US, Canada, EU)

Any team

A little help

Take this path if your design includes an exception to the module-level certification requirements or …

… you plan to roll out your product quickly in multiple markets and …

… nobody on your team has done this before.

DIY

Take this path if your design includes an exception to the module-level certification requirements and …

 

… you have the skills in house or want to develop in-house expertise.

 

Simple path

Most IoT devices built with ARTIK modules can follow a simple path to compliance with EMC regulations: properly reference the pre-certification that Samsung has obtained for the US, EU, Canada, and other jurisdictions. You print a label and your product satisfies EMC regulations. That’s (almost) all you need to do. Check the certifications page for a current list of certifications you can leverage.

I say “almost” because you need to avoid breaking the conditions under which pre-certification is issued. One potential problem is if the circuitry you build around the ARTIK module qualifies as an unintentional radiator. Common analog signal conditioning and power supply interfaces should not void the certification, but clocked digital circuitry might.

You also need to consider the antenna(s) you ship with your product. If you use the internal antenna built into some ARTIK modules there’s no problem. However, certification tests for radio modules with external antennas assume the antenna distributes the RF power equally in all directions. Look for omni-directional antennas with a gain of 3 dBi. Highly directional antennas can result in localized radiated power in excess of regulations. If you want to concentrate power toward the horizon at the expense of elevation you can ship Wi-Fi antennas with a modest gain of up to 6 dBi in the US. (See CFR §15.247 (4).)

A little help

For those not comfortable navigating regulatory waters, Samsung has assembled a set of Certified ARTIK Partners to help kickstart your IoT project. Partners specializing in product design have experience in shipping compliant products around the world, and they receive specialized training from the ARTIK team so they know all the details. I’d strongly suggest working with an experienced partner, at least for your first product. Even if you think you’re doing everything right, there’s no substitute for experience.

DIY

If your design falls outside the guidelines of ARTIK pre-certification and you have or want to develop the in-house capability to deal with regulatory bodies, you’ll need to work directly with authorized labs to obtain your own certifications. Here’s the process:

  1. Decide which jurisdictions you need to satisfy over the near term.
  2. Find labs who can issue certifications for all the jurisdictions you want. You’ll save money and time if you hire a single lab for all your certifications.
  3. Interview prospective certification labs and find the one you want to work with. Expect a pre-testing review where the lab will point out obvious problems before you waste money on formal tests.
 fcc logo  ce logo  industry canada logo

The US Federal Communication Commission allows you to download a spreadsheet with all approved labs around the world. In FCC nomenclature you’re looking for a Telecommunications Certification Body (TCB).

For compliance in the EU there’s an equivalent search tool. The lab you’re looking for is called a Notified Body if it’s located in the EU or Conformity Assessment Body (CAB) outside the EU.

 

Industry Canada offers a list of testing labs authorized to certify devices for distribution in Canada and internationally.

 

 

telecom certification screenshot
In the FCC search tool under “approved scope” select “A1” for certification at 2.4 GHz (CFR 47 Part 15 subsection C as a consumer device using ISM bands) or “A4” for 5 GHz (CFR 47 Part 15 subsection E).

Tip: By default United States open records laws apply to your submission of test reports and certification requests. You can invoke US Code of Federal Regulations 47 CFR 0.459 to request that your information be withheld from the public; there’s even a way to keep secret the fact that you’re filing at all. Ask your certification lab about equivalent privacy options for other jurisdictions.

Dig deeper

If you’re still with me I assume you’re looking for more details than “outsource this job.” So here we go: the path your device must take to legal compliance is subject to four types of mandates. Your certification lab will worry about what paperwork needs to be filed and exactly how testing is to be done so I won’t bore you with the details here. I’ll focus on certification impacts to your design and labeling mandates.

Let’s start with compliance issues for distributing in the US. When you see a label on an electronic device for sale in the US, you’ll see an acknowledgment the device “complies with Part 15 of the FCC Rules”. Specifically, this means the device complies with regulations published in the Code of Federal Regulations Title 47, Chapter 1, Subchapter A, Part 15 Radio Frequency Devices. Don’t even try to remember all that: the online Code of Federal Regulations is searchable, always up to date, and even allows you to see what changes occur.

Tip: FCC regulations pertaining to operation in the 5 GHz band (including 802.11a) changed in June 2016 as part of the Unlicensed National Information Infrastructure work.

With due disclaimers that this is a partial list of relevant items, here are a few snippets of regulations you should understand.

CFR §0.459   Requests that materials or information submitted to the Commission be withheld from public inspection.

(a)(1) […] Any person submitting information or materials to the Commission may submit therewith a request that such information not be made routinely available for public inspection. […]

(2) […] Where a party demonstrates that even the fact of a filing must remain confidential, and that this is consistent with the requirements of this section, this affidavit may be filed in paper format under seal.

CFR §15.1 Scope of this part.

(a) This part sets out the regulations under which an intentional, unintentional, or incidental radiator may be operated without an individual license. It also contains the technical specifications, administrative requirements and other conditions relating to the marketing of part 15 devices.

CFR §15.3 Definitions.

(h) Class A digital device. A digital device that is marketed for use in a commercial, industrial or business environment, exclusive of a device which is marketed for use by the general public or is intended to be used in the home.

(i) Class B digital device. A digital device that is marketed for use in a residential environment notwithstanding use in commercial, business and industrial environments. […]

Note: […] In the event that a particular type of device has been found to repeatedly cause harmful interference to radio communications, the Commission may classify such a digital device as a Class B digital device, regardless of its intended use.

CFR §15.212   Modular transmitters

[The section under which you can use ARTIK pre-certification to avoid the entire mess.]

CFR §15.247 Operation within the bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz.

(4) The conducted output power limit specified in paragraph (b) of this section is based on the use of antennas with directional gains that do not exceed 6 dBi. […]

Going Global

After you satisfy the EMC requirements for distribution in the US, you can’t just process a different set of paperwork to meet EU requirements (or vice-versa). Even though the European Commission process for CE compliance looks quite analogous to that of the FCC, the Harmonised Standards (ETSI) to which the EC refers are not mere translations of FCC Part 15 regulations. And when you see reference to Mutual Recognition Agreements they’re not saying the EU allows you to ship product in the EU because it passes FCC tests. They’re saying the lab that certified you passed the FCC tests is allowed to certify that you passed relevant CE tests.

The good news is that a good certification lab shields you from most of the details. It’s what they do for a living, they receive formal notice every time a regulation changes, and usually receive notice when regulations are going to change. They’re your best chance of making sure your product is compliant so you can get back to building a great IoT device.

About the author: Kevin Sharp has been an engineer since long before he got his engineering degree, and has extensive experience in data acquisition and control networks in industrial, retail, and supply chain environments. He’s currently a freelance writer based in Tucson, Arizona.