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6600M: Controlling a relay board (16ch)?

cfclaver Member ✭✭

Hi all,

Continuing with my Flex 6600M integration efforts...

I have gotten the basic integration done - RX, TX antennas, transverters, computer (mostly) etc... Now to push on the control I am looking one of the USB relay boards available. I am looking at a 16ch board. However I am getting confused on the compatibility based on the video tutorials and comments here in community. The confusion stems from USB cable type and communications compatibility / protocol.

The board I am looking at is at the link provided at the bottom. I'd like to know if others have had success interface a Flex 6000 series to this board or something similar.


1) Do all boards share the same communication protocol? SainSmart seems to be what works. Is this a required protocol for use with the Flex? What should I be looking for when selecting a board?

2) Is the FTDI chipset a must for USB controlled boards. The FTDI chipset seems to be meant for conversion of USB to RS232. What is required for the Flex to recognize the board using the built in USB port(s)?

3) Is there a list on boards that are known to work with the Flex 6000s and SmartSDR? Should I plan on just using a known 8ch board?

Thanks as always!


Chuck - NJ6D / N7KU



Best Answer

  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin
    Answer ✓

    FlexRadio's external USB devices, such as the Sainsmart relay boards, offer versatile options for users. These devices don't rely on traditional RS-232 communication but utilize a BIT Map model. This approach allows you to control them effectively, and you can even use multiple boards simultaneously, expanding your capabilities. To manage multiple boards conveniently, it's advisable to employ a USB power hub, which ensures they all receive power and can operate seamlessly from a single source.

    When using external devices with a FlexRadio system, it's crucial to select ones with an FTDI Chipset. The FTDI chipset is preferred because it ensures reliable and consistent communication between the FlexRadio system and the external devices, minimizing compatibility issues and maximizing performance.

    By choosing FlexRadio-compatible external USB devices like Sainsmart relay boards with the BIT Map model and FTDI Chipset, you can enhance your radio setup's functionality and control, making it more versatile and efficient for various applications.


  • Hi Chuck, I have used several of the Denkovi 8 channel USB realy boards and it was easy, no special drivers or configuration.


    The board you show seems "No Name" so I personally wouldn't get it.

    There is documentation in the Flex Document:

    SmartSDR USB Cable Interface Guide


    Good luck,

    Mark K6UFO

  • Geoff AB6BT
    Geoff AB6BT Member ✭✭✭

    I have not looked into using these relay boards with Flex but I have used them in the past for other projects:

    They do make a wide variety of relay boards with a number of different interfaces.

    Might be worth checking out...

  • KD0RC
    KD0RC Member, Super Elmer Moderator

    Hi Chuck, what are you looking to control with the relay board?

    I designed a system for the Tampa Amateur Radio Club that senses when all clients have signed off the radio and opens a paraDan antenna disconnector. It also chooses external bandpass filters, and if two multiFLEX stations are on different bands, it disengages all filters.

    It is based on the Teensy 4.1 board with the Ethernet connector ($35ish, USD). If you are interested, the info and code is under my call on GitHub.

  • cfclaver
    cfclaver Member ✭✭


    Thanks so much for the fast feedback! To summarize my understanding...

    Flex is basing its communications to the external world via USB using the FTDI chipset for reliability reasons. Check got it! For relay boards it is important to be sure the board utilizes the FTDI chip set as the USB conversion interface. With an FTDI chip set on the board a standard USB-A to USB-B cable (or whatever a particular board is using) should do the trick.

    It seems relatively easy to find 8ch boards with the FTDI chip set. For 16ch boards the jury is still out on positively identifying one with FTDI.

    I now know what to look for in search for a relay control board. I will try to respond here again if I find a 16ch board that fits these Flex requirements.

    Best n& 73s,

    Chuck - NJ6D / N7KU

    P.S. My first control objective it to run some TR switching for on mast/tower relays (Tohtsu type) for LNA and filters - particularly for my 6m EME efforts. Also, I have already successfully completed a 6m EME QSO, using just the plain vanilla 6600M - no external LNA at the antenna - at lunar apogee to boot! The 6600M has a very good receiver.

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