Welcome to the new FlexRadio Community! Please review the new Community Rules and other important new Community information on the Message Board.
If you are having a problem, please check the Help Center for known solutions.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.

True line out - any possibility in the future?

Chuck - KJ6HTChuck - KJ6HT Member ✭✭
My search found several related comments and questions but nothing related to future possibilities. The current line out supplied on the ACC connector is a buffered output of the powered speaker left and right channels. This means that if you have multiple slices open this output is a mix of all and is affected by volume adjustments. Are there any future plans to change this output so that it can be a true line out not affected by what volume is heard on the speakers? Would this require hardware changes or could it be accomplished with firmware? The best option would be the ability to associate the line out with a specific slice and have the level constant. Without this capability the radio is severely limited for any mode that requires external equipment such as hardware modems.

Completed · Last Updated


  • edited May 8
    The radio was not intended to have separate line outs for external modes.  With the majority of digital modes now supported in software, that functionality is supported by DAX.

    It would be very simple to use a computer to take a DAX channel and output it to a real line out if that was truly required for some digital mode not supported in software on a computer.

    The radio can hardly be described as "severely limited" - the specifications of the radio are very clear.

    It is impossible to please every one with every single use case - the radio has a lot of flexibility for typical ham operations.

    Stu K6TU
  • Chuck - KJ6HTChuck - KJ6HT Member ✭✭
    edited May 8


    Thank you for the response but I respectfully disagree. I did not describe the overall radio as "severely limited". I said "Without this capability the radio is severely limited for any mode that requires external equipment such as hardware modems". Many hams use hardware modems, one example is the SCS P4Dragon for Pactor. There is not a software equivalent for many of these devices.


    My question was regarding future possibilities, I am not attacking Flex, just asking a question. There is no need to come to the defense of Flex so vigorously, I too am an owner and supporter.  

  • edited August 2016
    Sorry if you read my response as anything other than a factual answer.  I didn't take it as an attack but such comments even with qualifiers tend to get misread by the lay reader and need appropriate calibration.

    Back to coding.
    Stu K6TU
  • pa0biepa0bie Member
    edited September 2015
    The TREU line out will need more ADC's as available.  There is no hardware modification planned for the FLEX 6000 serie.
  • Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
    edited May 8
    I am afraid that individual analog audio lineouts is not possible with the current FLEX-6000 hardware.
  • Bob N7ZOBob N7ZO Member ✭✭
    edited December 2016
    Are fixed (or independently adjustable) levels possible on the line outs?
    Are the line outs from their own DAC's or just split off of the speaker DAC's?
  • edited August 2016

    There is ONE line out.  It is a mix of the audio outputs of each slice where the individual slice level is set by the slices own audio level.  The master volume control adjust the mixed level.

    If you want independent line outs, then use DAX and appropriate software on a PC to take a DAX stream and turn it into a line out.  Then you will have independent line outputs with separately controllable levels.

    There are a number of USB connected professional grade mixers that would support this kind of operation.

    Are there really that many hardware modems out there that this is a requirement?  I still have a PK232 but its now 30 years old and hasn't been powered on in 20+ - gone the way of the Dodo because of software.

    Stu K6TU
  • Bob N7ZOBob N7ZO Member ✭✭
    edited December 2016
    Hi Stu,

    My application is an SCS PACTOR modem (the same family of modems Chuck mentioned).  I use this modem for Winlink 2000.

    As SSDR gains functionality, I have been moving operations away from my Elecraft K3 and to the 6700.  Eventually, I would like to take the K3 out of service.  But currently, as the K3 has fixed (adjustable in menus only) line level outputs and the 6700 does not, the SCS modem remains attached to the K3 where it is very reliable and easy to use.

    I consider routing DAX outputs back to an external USB DAC unnecessarily complex and the needless addition of outboard hardware.

    Looking at the 6000 series hardware manual, I see two line outputs:
    7.4.2 Pin 2: Line1 Out
    This audio line output is a buffered output of the POWERED SPEAKERS left channel.
    7.4.3 Pin 3: Line2 Out
    This audio line output is a buffered output of the POWERED SPEAKERS right channel.

    ...not that it really matters as I need only one fixed output for the SCS modem.

    The manual does use the term "buffered", but it is not clear if this means buffered with physical analog hardware or just logically buffered with the possibility of this being accomplished with dedicated DAC's.  It is this question that I hope Tim answers.

    By the way, I am looking forward to trying your latest iPad app.

    73, Bob, N7ZO
  • edited December 2016
    Thanks for the question.  I had been meaning to ask as well.  I too was wondering why there was no line out capability on the radio.  On other equipment I use the line out into my mixer and then control volume and on that channel into the main mix.  While you can do this on the flex, it is affected by the volume control.  My understanding of line level out was that it was not affected or controlled by the volume controls on the device but maybe I'm just confused.  I must say though, I was dissapointed to find that the accessory plug output was not a true "line level out" port.

  • Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    "Are fixed (or independently adjustable) levels possible on the line outs?"

    Yes.  There is a feature request to make the gain level adjustable.

    The line out L/R channels originate from the same DAC output as the powered speakers, but they are 180 degrees out of phase.
  • Lee - N2LEELee - N2LEE Member
    edited December 2016
    I would like to be able to use an SCS modem as well and I have the same concern as Bob. Having the ACC output be controlled by the volume control is an issue. Unfortunately it looks like a Signalink or similar product is the only way around this problem. :(

Leave a Comment

Rich Text Editor. To edit a paragraph's style, hit tab to get to the paragraph menu. From there you will be able to pick one style. Nothing defaults to paragraph. An inline formatting menu will show up when you select text. Hit tab to get into that menu. Some elements, such as rich link embeds, images, loading indicators, and error messages may get inserted into the editor. You may navigate to these using the arrow keys inside of the editor and delete them with the delete or backspace key.