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Voltage indication when antenna 2 is selected ?


I would like to activate a relay whenever antenna 2 is selected on my 6500.

Is this possible ?


  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin

    Bill, In this post, you asked a question where you wanted to get an answer, but the post was designated as a discussion topic. Please see the Message Board post Using New Q&A (Question & Answer) Feature for how to create a Question and Answer (Q&A) post. I went ahead and converted your post to a Q&A.

  • Alan
    Alan Member ✭✭✭✭


    You can operate a 5VDC relay using a USB cable available from Flex

    Use the "BIT" configuration as described in the Flex USB Cable Guide:

    Alan WA9WUD

  • Bill  /  VA3QB
    Bill / VA3QB Member ✭✭


    The Flex Cable is very expensive. Would cost me over $100 Canadian with taxes and shipping.

    Would a USB to Parallel cable from Amazon work with the following circuit I found online.

    Bill VA3QB

    Quote :

    For more than a few relays, a USB to printer parallel port adapter gives you 8 actual data lines plus a number of printer port control lines that are under computer control. In most cases you will need a buffer IC to allow the logic level signals to drive relays. A ULN2803 IC, a USB to parallel printer port unit and a power supply suited to the relay operating voltage is all that will be needed.

    Replace resistors and LEDs in this diagram with relays.

    Zener optional. If not used connect V+ to pin 10.

    V+ shown as 9V but choose to suit relays.

  • Alan
    Alan Member ✭✭✭✭


    In order to not "overload" the Flex USB port, I found using only official "FTDI" cables, of the proper voltage output, is a must. Yes you can use the non official FTDI cables, but I found they caused problems with the Flex Server. In those cases, I found the Flex Server would shut itself down to protect the USB port.

    Here are links to the official FTDI parallel cables on Amazon (same as offered by Flex). Note very carefully, there is a 3.3 Volt cable and a 5.0 Volt cable:

    I like to use relay boards that provide optical isolation. Here is an example that I have used with the Flex BIT USB / FTDI parallel cable;

    Here is a diagram of the relay module shown above. I prefer to remove the jumper and power the relay coil from an external 5 VDC source. Doing so reduces the milliamp draw from the Flex Server USB port. If you use an external relay board voltage source, you can then use a 3.3 Volt FTDI cable from the Flex Server, if you prefer:

    I do not have experience using USB Relay boards with the Flex USB BIT cable. Perhaps others can give you their experience with various cables and relay boards for that configuration.

    Alan. WA9WUD

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