M5Dial based CTR2 hardware is available in three different configurations. All three variations run the CTR2-Flex firmware that provides Bluetooth/USB MIDI control for third-party apps like SmartSDR for iOS, SDR-Control, FT-Control, TS-Control, K4-Control, Thetis, and SDR-Console and direct control of your Flex radio over WiFi using the Flex network API.
CTR2-Uno (formally the single-knob CTR2-Flex hardware), has a single programmable knob with and a dual-function 3.5mm input jack for either paddles or key/PTT control. You can find its hardware manual here.
CTR2-Duo (formally the dual-knob CTR2-Flex hardware), has two programmable knobs and a dual-function 3.5mm input jack for either paddles or key/PTT control. You can find its hardware manual here.
CTR2-Quad is the latest hardware configuration. This unit has four programmable knobs, two programmable pushbuttons, and separate 3.5mm paddle and key/PTT input jacks. You can read its manual here, or click the download button to download a copy of it.