Thursday, October 11, 2012

Domestic Unlicensed Modular Radio Approval


Transmitter (Photo credit: Thorius)

What is a modular approval, how does one qualify for one, and what are some of the advantages and disadvantages in selecting to pursue a modular radio approval. I’ve addressed these questions in summary form here, and I provide some links for further reading.

A modular approval allows the approved product to be installed in different host devices, without the need for additional testing or authorization for the transmitter for each host system. Note that the host itself may still require authorization or reauthorization depending on the host, but the transmitter would not need to be recertified for each host.

There are 4 types of modular approvals;

1. Single-Modular transmitter

2. Limited Single-Modular transmitter

3. Split-Modular transmitter

4. Limited Split-Modular transmitter

A single-modular device is a device in a single package, and a split-modular is one where the radio front end and the control elements section may be separate.

The use of the word “Limited” indicates that the device may have certain grant conditions or be reliant on a specific host configuration for compliance. Integrators are cautioned to pay close attention to these limitations.

To qualify for modular approval, the device must comply with 8 specific conditions. For a Single-modular transmitter, the device is a self contained, physically delineated component that can demonstrate compliance independent of the host.

1. Radio circuitry must be shielded

2. Modulation / data inputs must be buffered.

3. Power supply regulation on the module

4. Permanent antenna or unique connector

5. Must demonstrate compliance stand alone (outside host)

6. Labeled with its own permanently fix FCC ID, or have electronic display capability

7. Must comply with applicable rules, and with grantee provided conditions

8. Must comply with applicable RF exposure requirements

A limited modular approval may be granted when a device does not meet all 8 of the conditions, but may rely on a specific host and applicable operating conditions for compliance. For instance, the shielding, buffered I/O or power regulation may be provided by a specific host. In these cases the module would be “Limited” to the specific host providing those requirements.

The first and probably most obvious benefit to a modular approval is that the radio module would not need to be recertified for every host installation, thus saving time and money when incorporating radio functions into multiple host devices. Other advantages may include;

· Changes to the host don’t affect the radio certification (except on “Limited modular”)

· Time to market for a new host is considerably less if the product does not require certification

· Ease of managing the radio certification, one FCC ID instead of many.

· Flexibility with installation within the host (except maybe on “Limited modular”)

· If the module is the product, it’s more attractive for an integrator to use a pre-certified device.

· The radio may be “End-User” replaceable (potential upgrade or repair)

Some items that may be negative points to a modular approval;

· Radio generally more expensive due to shielding, buffered i/o and power regulation

· Depending on host/antenna placement, transmitter power may be less than non-module type

· Integrating multiple transmitters (co-location) within a single host can be problematic

Things to pay attention to when using an already approved module;

· Be aware of the type of module and grant conditions or restrictions

· The term “Modular approval” is specific, if unsure check the FCC ID and look at the grant

· Follow all installation instructions and warnings provided by the grantee

Other things to possibly consider are RF exposure and/or hearing-aid compatibility, for devices with specific antennas, or specific host/enclosure configurations. The FCC has published a “Transmitter Module Equipment Authorization Guide”, KDB 996369, and I recommend reading through the guide if considering the modular approach.

To check a prospective module’s FCC approval, have the FCC ID ready and visit;

Keep in mind, the first 3 characters of the FCC ID are the Grantee Code, and note that the numbers 1 or 0 will never be part of the grantee code (to avoid confusion with the letters i and o). The grant will clearly indicate “Modular Approval” or “Limited Modular Approval” (LMA) if the device is so approved. At the time of writing this article, the FCC system only searches based on the legacy system of 3 digit grantee codes, however, the FCC is moving to a 5 digit grantee code system real soon – see

Compliance testing and certification costs of a Single-Modular transmitter are comparative to that of a non-modular approval of the same radio in most cases, in some cases it could be less expensive due to the simplified test setup and configuration of the module. Time and cost of Limited-Modular devices can vary depending on the host.

Of course this all applies to domestic FCC certification, but what about other regions?

Canada has a very similar approach to radio modules, see RSS-Gen, section 3.2.2 for details. In Europe, there is no “Modular Approval” process as the system is based on self-certification, but a somewhat similar approach can be taken, please see my article “Radio module integration and R&TTE compliance” for dealing with radio modules under the R&TTE Directive.

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