Introducing xKEY – Remote Keying Interface for the Flex

Mario, DL3LSM has announced xKEY – Remote Keying Interface for the Flex.  He writes:

Today I want to write about my latest project, a Remote Keying Interface for the Flex 6000 series radios running on macOS.

After having the radio with me for a year now to update xCAT and xDAX for multiFLEX and not being able to operate (no antennas here) I want to bring the radio to its remote location as soon as possible and start operating again. But the prospect of going nearly 100% FT8 again like the time before was really not exciting. I really want to operate CW again…

But there are no good solutions for remote CW for the Flex if you don’t want to restrict yourself to CWX.. And buying a Maestro is out of budget.. But the API commands and features the Maestro uses for its CW operation are there and I decided to use them in a client application for the Mac called xKEY, a Remote Keying Interface.

The app has two purposes:

  1. Connecting a key (straight key or paddle) or an external keyer remotely to the radio
  2. Providing a low latency local sidetone to the operator.

Communicating with the radio was the easier part of the project. More thoughts went into interfacing the key or a keyer (like a Winkeyer) to the Mac computer.

There is a similar project for Windows computers from Matt, NQ6N ( which uses a serial port for the keyer interface. Maybe I was to lazy to build that simple interface so I looked for another solution. And I discovered the Teensy family of micro controllers ( What has sparked my interest is that the USB interface on these controllers can be configured to show up as a MIDI interface on the computer. And the Mac has low latency MIDI “on board”.

The project needs some more finishing touches before I can release it (especially writing the setup guide) but I wanted to give a little video teaser for the project (to see if there is interest). And here it is, my first video:

More information and download information can be found on Mario’s blog at where he posts information about future updates to the applications.