Pros and cons of preapproved wireless modules

Using ‘preapproved’ wireless/radio transmitter modules does not eliminate testing, but it can eliminate the need for certification and reduce the amount of testing required.

Judicious selection of a preapproved module can give you the following benefits:

• Reduced testing costs
• Elimination of the certification process and associated fees
• Much faster time to market, since complex testing and lengthy certification processes are avoided.
   

The design engineer must be mindful that not all preapproved modules are the same and that the module’s type of approval might result in restrictions on its use and the need for further testing or certification. For example, the selection of a wireless module that has ‘limited modular approval’ will require more testing and additional certifications than a product using a module that has a ‘single modular approval’.

Other common restrictions include:

• A limit on the gain of the antenna
• Restrictions on the trace design of the antenna
• Rules for the co-location of other transmitters
• A minimum separation distance of the user from the antenna.
   

The USA (FCC), Canada (ISED) and Japan (MIC) have similar rules on the use of preapproved wireless modules. In contrast, Europe’s Radio Equipment Directive (RED) 2014/53/EU permits a self-declaration approval process which does not require product certification or regulator involvement; however, the RED requirement for more extensive immunity testing makes using CE marked preapproved wireless modules a more expensive process than testing for North America.

The regulator in Australia, the Australian Communications and Media Authority (ACMA), requires product compliance under various labelling notices and labelling with Regulatory Compliance Mark (RCM). It is important to note that wireless modules are considered to be components under the ACMA regulations and hence they should not be labelled with the RCM. The original test reports provided by the module manufacturer can be used to reduce the amount of testing on the composite product.

Conclusion

The selection of wireless module for your design is fraught with risk. Careful consideration of all factors will provide benefits in reduced testing and certification fees, reduced chance of test failure and greatly reduced time to market.

For more information, contact EMC Technologies.

Image credit: ©iStockphoto.com/Mauro Saivezzo

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