The benefits and downsides of using radio modules in North America

A radio module is a stand-alone radio transmitter or transceiver that incorporates in a single unit all the components required to support radio functionality. A so-called single module transmitter is designed to function independently of any host product. As such, it must demonstrate compliance with all applicable approval or certification requirements prior to being placed on the market.

The use of pre-approved radio modules can provide manufacturers with an efficient path for integrating proven radio functionality into their devices. But pre-approved modules can also introduce some unexpected challenges that can delay device approval, and even result in the need to redesign a host product from scratch.

Based on our extensive experience in testing systems and devices with integrated radio functionality, here’s our take on the potential benefits and downsides of using pre-approved radio modules when obtaining device certification for the U.S., and Canadian markets.

The benefits of pre-approved radio modules

The biggest single advantage of using a pre-approved radio module in a system or device is that the module has already been shown to be fully compliant with applicable requirements. For example, radio modules that are authorized to the U.S. Federal Communications Commission (FCC) requirements have already been tested and certified for electromagnetic interference, radio frequency (RF) exposure, and radio spectrum limits consistent with the module’s intended use. Pre-approved modules are also tested and approved for use with specific antenna.

Integrating a pre-approved radio module into a system or device eliminates the need for the host product manufacturer to design communication functionality from scratch. This benefit alone can significantly reduce the time and the cost associated with designing a product from the ground up. Using a pre-approved module can also allow a manufacturer to take advantage of current industry innovations in communications technologies, thereby improving the overall value and marketability of their system or device.

Another important benefit comes from the reduced need for testing of the host-product. Since a pre-approved radio module has already been tested for radio-specific compliance considerations, verification testing of the host product is more limited, and the approval process for the host product is streamlined. Once again, these advantages can save the host product manufacturer time and money and allow them to generate sales revenue more quickly from the sale of their approved product.

The potential downsides of integrating pre-approved modules

Now let’s look at the other side of the equation, that is, the potential downsides of using pre-approved radio modules in a host product.

First, not all module pre-approvals are the same. Some modular approvals will have restrictions outlined concerning their approved uses. For example, a module might have been designed exclusively for use in a specific type of host product or a specific application. When integrated into a different type of host product, the use of a limited modular transmitter might then require additional testing or evaluation of the host product and certification.

In a similar way, a second potential downside from the use of a pre-approved module is the limits or restrictions it places on the host product design. To illustrate, even a fully compliant single modular transmitter might be approved for use with specific type of antenna, or one utilizing a specific power gain. This could limit the ability of the host product manufacturer to modify the antenna specifications or offer users certain upgrade options while continuing to use the same pre-approved module, without first performing assessment and certification for the original module to add the new antenna or submitting their host product for regulatory review and approval.

A third potential downside of a pre-approved radio module is the out-of-pocket cost. For obvious reasons, integrating a radio module that has undergone regulatory review is likely to be priced to reflect the additional effort on the part of the module developer. Having committed to use a specific pre-approved module also limits the host product manufacturer’s ability to source the module from other suppliers. Depending on the technical complexity of the radio module requirements, it might make economic sense for a host product manufacturer to consider the option of developing their own proprietary module design.

Similarly, a module manufacturer can independently decide to cease production of a particular line of pre-approved modules, or to make design modifications or technical changes that render the module unusable for its intended purposes in the host product. Again, this potential downside sets the stage for ongoing uncertainty regarding the availability of a key component and requires the host product manufacturer to regularly evaluate their potential courses of action in the event of such a change.

Finally, although the U.S. and Canada currently allow for the use of pre-approved radio modules in host products, other countries limit their use to certain applications or don’t recognize their validity in assessing the compliance of the host product. These limitations mean that host product manufacturers with integrated pre-approved radio modules may still be required to conduct the full range of testing required by that country’s regulatory authority, thereby negating many of the potential benefits of using a pre-approved module.

So which path should host product manufacturers take when it comes to pre-approved modules?

Given the potential benefits and drawbacks of pre-approved radio modules that we’ve presented here, it should be clear that the decision to use or not use a pre-approved module is not a simple choice. Instead, each manufacturer must conduct their own thorough risk/benefit analysis regarding the use of a pre-approved module in their host product. Such an analysis would also benefit immensely from exploring the module options available from multiple developers and, finally, from confirming your analysis with qualified, third-party experts before moving forward.