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Clarification on FCC Requirements

We have been investigating the exact requirements (as of now) for the Part 15 radios used in WISP deployments. To try to clear things up some, I decided to try to summarize what we have learned over the past year or so and try to help others to understand exactly what is required and expected. That said, I am not a lawyer and my general disclaimer would be to use this information as a guide and not as the final word. The final word, as always, resides with the FCC in the USA and other regulatory organizations in other countries.
To spell it out:
All that said, FCC certification can really be broken down into two parts: Subpart B and Subpart C certifications.
Let's take a look at what each of those is:

  • Subpart B:
    This is for unintentional radiators, meaning that any electronic devices that have signals will put out interference. Because of this, the FCC requires this interference to be measured to make sure it complies with the guidelines that have been set by the FCC.

  • Subpart C:
    This is for intentional radiators, meaning that the device is intentionally transmitting RF (AKA a transmitter). The FCC has set certain rules for these transmitters based on band, modulation, etc.

Now that we know what the two parts of certification, we can talk about what the requirements for each are. There are two types of devices on the market today (that I'm aware of at least): complete systems and certified modules.

  • Complete systems are those systems that are certified as a whole; meaning that the certification includes everything from the power supply, to the enclosure, the radio card / PCBA, pigtail, etc. It was tested as a complete system and is therefore marketed as a complete system. Any changes to the complete system (enclosure, antennas, etc.) void the certification and must be re-certified. There are exceptions to this which are covered later. Complete systems carry an FCC ID that covers Subpart C requirements and a Declaration of Conformity that covers Subpart B requirements.

  • Certified modules, on the other hand, have been tested to meet the standards as a stand-alone device. For example, a mini PCI card may have been tested without any housing, etc. There are certain requirements that must be met in order to be certified as a module, but once it is certified, all Subpart C requirements are met automatically when the module is integrated into a final system as long as the stipulations written on the grant are met. In this case, the module carries the FCC ID label to cover Subpart C requirements. In order to meet Subpart B requirements, however, the final system MUST STILL BE TESTED and covered under a Declaration of Conformity. The final system must also have a label on the outside that says: Contains FCC ID: xxxxxxxxx. The grant notes section of the FCC grant must say Modular Approval.

There are some exceptions to these rules. For antennas, any antenna of the same type and lesser gain may be used with either a certified system or a certified module. By same type and lesser gain, it means that if the certification has a 12dbi Omni, other omnis that are <=12dbi may be used by the installer. Also, different lengths of coax can be used with certified systems and modules.

So what does this really mean for the WISP? It ultimately means that the device you are using must either:
  1. Have a modular certification for the radio inside AND have a Declaration of Conformity to comply with Subparts C and B respectively OR
  2. Have a system certification for the complete system (covers Subparts C and B both)

The easiest way for a WISP to tell if a system is FCC certified is by the required label on the device. For #1 above, there should be a label on the outside of the device that says Contains FCC ID: XXXXX and have the Declaration of Conformity on the label as well or in the manual. For #2 above, there should be a label on the outside of the devices that says FCC ID: XXXXX and have the Declaration of Conformity on the label as well or in the manual.
My final comments are on changes and what it means for the certification. I have created a matrix that covers complete systems and certified modules as well as some common changes:

As I said before, this is to be used as a guideline. If you have specific questions or concerns, you can ask the FCC lab directly at this link:
»gullfoss2.fcc.gov/prod/oet/cf/kd ··· sult.cfm
This site contains the FAQs for most of the items covered above as well as a link to Submit An Inquiry on the left nav. I encourage all of you to read through this information and ask questions if you have them.
To search for FCC grants, you can use this site:
»gullfoss2.fcc.gov/prod/oet/cf/ea ··· arch.cfm
I hope this information helps to give you a better idea of the FCC certification requirements!
-Harold Bledsoe

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by dongato17 See Profile edited by seagreen See Profile
last modified: 2006-07-26 14:20:44