CTR2-Max-5

September 18, 2026

1. CTR2-Max-5 units are in stock and ready for next-day shipment
2. USPS has changed the way it handles international shipping costs. Please see my post here for more information.

CTR2-Max-5 (Max) is the latest addition to the CTR2 controller family. It has the same functionality as CTR2-Quad in that it supports Bluetooth and USB MIDI control and works with many radio control apps like SmartSDR for iOS/MacOS, AetherSDR, RimuSDR, OnlineRemoteRadio, and RemoteTx. It also supports direct Flex radio control over Wifi using the Flex network API (called Flex WiFi mode).

In addition, it features a much larger touchscreen display (2.8″ compared to 1.28″ on the Quad), one additional knob, and two additional buttons.

Normally, in Flex WiFi mode, Max connects to your radio as a non-GUI client. In this mode, Max runs in parallel to the main GUI client connected to the radio (i.e. SmartSDR for Windows, or iOS/MacOS, AetherSDR, RimuSDR, etc),  A new feature has been added to Max that allows you to connect to your radio as a GUI client, when no another client is connected. In this mode, a mini-panadapter is displayed,

Because MIDI mode is a one-way protocol, the mini-panadapter is not available in MIDI mode.

Unlike previous CTR2 controllers which use a piezo buzzer for sidetone (when operating in direct Flex control mode), Max produces a true sinusoidal sidetone with full pitch and level control. The output of the codec feeds a 1.2 watt amplifier that drives an internal speaker. Not only is the sidetone easier to listen to, an optional sidetone audio interface option allows you to patch the transformer-isolated sidetone from Max to your headphones, powered speaker, mixer, or PC sound card. See the limitations of this option below.

Max is also designed to support up to a 2000 mAH internal Lipo battery. Two battery input connectors allow for different battery connector polarities. A battery isolation switch totally disconnects the battery when not in use to preserve its charge. A 2000 mAH battery will power the unit for up to 12 hours. You can enable a battery icon to monitor the charging/discharging state of your battery.

NOTE: Due to shipping restrictions, the user must supply and install the battery. They are readily available at Amazon and other online retailers. More details on installing the battery can be found in the CTR2-Max Hardware Manual,

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Please enter your call sign in the Add a note to your order section on the Checkout page so I can create your registration key.

Failure to do so may delay your order.

Also, if you’re planning on using CTR2-Max-5 in MIDI mode with a radio control app, let me know which app you’re running in the Add a note to your order section on the checkout page and I’ll load that app’s configuration into your unit. This way, you’ll  only need to import your app’s MIDI map from the CTR2-Max Config Files page to be ready to go.

You can find the list of control apps I have configurations for, and the map files for them, on the CTR2-Max Config Files page.

If you don’t specify a control app configuration, your unit will ship configured for SmartSDR for iOS/MacOS.

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