February 19, 2022: I uploaded a new default file structure. You should use this structure if deploying CTR2 for the first time.

CTR2 uses the built-in micro SD card slot on the Teensy 4.1 development board to store setup data, audio Tx buffers, off-air recordings, and voice announcement files. The micro SD card slot on the Teensy Audio Adapter board is not used.

While it is possible to just plug in a micro SD card and run CTR2, this is not recommended. CTR2 will create the necessary folders and default files, but it cannot create the .WAV files used for frequency and mode voice announcements.

For full functionality, download, extract, and copy the folders in the CTR2_Default_micro-SD_Files_v1xxxx.zip file below to a blank micro SD then insert this card into the micro SD card slot on the Teensy 4.1 development board. The micro SD card can be up to 256 GB but a 16 GB card is usually more than sufficient. These folders provide the basic folder structure for CTR2 with a few frequencies loaded in the common and first radio port’s frequency lists.