Add-on boards are additional circuit boards that can be added to Icom radios to enhance their functionality. These boards are designed to provide specific features or capabilities that may not be included in the standard radio model. Examples of add-on boards include voice scramblers, digital signal processors, GPS receivers, and data modems. These boards are typically installed by opening the radio's casing and plugging the board into a dedicated slot or connector. Once installed, the add-on board can be activated and configured through the radio's menu system. Icom offers a range of add-on boards for their radios, allowing users to customize their radios to suit their specific needs and requirements. Whether it's for professional use, amateur radio, or recreational activities, Icom Add-o...