OpenEar: An Easy to Use Windows TETRA Voice Decoder

A new TETRA voice decoder called "OpenEar" has just been released. The program is a standalone Windows app that directly connects to an RTL-SDR. Decoding a TETRA voice signal is as simple as opening the program, tuning to the TETRA frequency and clicking on the signal. With good signal strength voice comes through very clearly. CPU usage on our PC is also minimal. 

The program source is currently not available as the author notes that he only intends to release it as open source in the future once the project is completed, and right now this is only the first early release. Right now the program is just an .exe with a few .dlls. You'll need to first install the Microsoft Visual C++ Redistributable Package linked in the Git readme. Just in case, we virus scanned the exe and tested the program in Sandboxie. It appears to be clean, and it works as intended.

In the future the author hopes to support many more protocols such as DMR, MPT1327, ACARS, AIR, GSM and more. In order to support his work he is asking for Bitcoin donations, and the donations link can be found on the Git readme.

UPDATE 1: If you're getting missing dll errors and you already installed the Visual C++ Redistributable, try downloading the missing dll's from There should only be about 5 missing.

UPDATE 2: As pointed out in the comments by Steve M. from Osmocom, this software may be in violation of several GPL licences as no source code has been released and it appears to rely on GPL code and libraries. Please take this into account.

UPDATE 3: As per update 2, the author has decided to temporarily disable the TETRA functionality pending a rewrite of the code that he will complete within one to two months). Instead he has added DMR decoding.

OpenEar TETRA Voice Decoder Screenshot
OpenEar TETRA Voice Decoder Screenshot


  1. Paul

    Problem is because Some people can copy or write there own software and the majority of people cant they take advatage of this, this software in my opinion needs a total re write as its breaking laws and I am glad that some one also has the same outlook on it as me. we always get people coming back saying we are wrong etc but am used to that as people are blind when it comes to the truth or when they are getting somthing out of it for themselfs

    • moneriomaa

      i do not understand your meant! you can search on net and find many many free software without code!
      how you can detect which of them used which codes! or how you can find that really they used others codes or not? you said that you never used free software without code!
      It seems that you usually believe everything you hear without research or that you are the same person with a new name!!
      i have suggestion for you, please try to spend your time to kill free software pages or force them to publish their codes! How can you judge when you have no information about the history of this software? If you can make an example or think more in speaking, yes i know some people like to comment on everything without any investigation, they can comment about weather in 6:00pm and comment about free software on 6:05 pm good job continue that, and note if creating or porting new software is possible by copying it must be many software like openear before it, then their codes is not usable for creating software, i removed software from pages and wait until another body to creates another programs like this, and you can be glad that some ones like you prevent to others using free software! i think i waste my time on this field

      • Harald "LaF0rge" Welte

        @moneriomaa: “Free Software” is about freedom, not about “free of charge to download”. The Freedom of Free Software includes the freedom to _modify_ the software, for which source code availability is fundamental. See Free Software at wikipedia, if you really should not be aware of that by now.

        What you call “Free software” in your paragraph above is Freeware, i.e. software distributed free of charge in binary form, without any source code.. It has _nothing_ to do with Free Software!

        For many developers who spend weeks, months or years of their lives in writing Free / Open Source Sofware (FOSS), the key motivation is that forever, this software, and any modifications/derivatives of it, will be available in source code form to anyone. This is why they release their code under a so-caled “copyleft” license, such as the GPL or AGPL.

        Creating derivative works of such software (such as, for example, librtlsdr or osmo-tetra) is a copyright infringement _unless_ you follow the license text. And that license text means (among other things): You have to provide the complete and corresponding source code!

        Full Disclosure: I am the main developer of osmo-tetra, which was illegally used in openear. I’m also the person who filed the DMCA complaint with github, because @monerioma would not otherwise stop using it in his non-free-software openear. I coincidentially also am the founder of, where I have demonstrated repeatedly that the terms of the GNU GPLv2 can be enforced in and out of court even against large multi-national corporations. Everybody using open source software must follow the license terms. And in caes of GPL/AGPL, that means: You must provide the complete and corresponding source code.

        • Vselic

          So why dont you provide us decoder/decryption for basic privacy mode motorola, hytrra for free, if you are so smart?

          What about tetra???

        • moneriomaa

          i am not agree with you in some points, i did not modify to your code or your team code! openear is not laboratory codes that needs library or some packages or compiling procedures! i designed openear from more than decade experiences on comint, it is not for developer it is for users, some times users think ok openear created with copy and paste, It has been stolen,… finally i removed it for all users that needs download linux iso and all packages and libraries with conflict and … then they can compile it and find errors and try to solve it, i think it is better for all challengers, about tetra I designed my own 8psk demodulator (changed msg decision to pi/4dqsk) it is not burst demodulator and it is fix continues demodulator, then it is not for you or your team, you or your team used linux library if i remembered correct its name is gnuradio but i did not use it because it is hard for using in windows complier for easy openear software i used my own demodulator you and you user of team can check it easily by output of signal , then it is about bit process and frame and coding in first version before i remove it from openear, yes i used other projects but i removed it to change completely used code and note that tetra is open documented and you and your team is not creator of Tetra you and your team studied those documents and why others can not?! , and about vocoder it is completely used from etsi or itu (i can not remember it now) and not from your project.
          some people makes their world limitation to staying on challenges, because They are satisfied with this and feel a sense of progress but i have no benefit to share openear with others also with challenges of others, it is funny state that i try to create software that user can easily uses it by click and also i must challenges with others, really I was bothered, anyway i removed software from public domain and then no body can request for binary or code!

          • Harald Welte

            It’s sad you did not comment at all on the

            The discussion is not about the quality of software. osmo-tetra is well known to be outdated and incomplete. It was an interesting research/hack at the time. However, anyone, including you, is always more than welcome to contribute any improvements. That is what free software is all about: About collaborative development, where everyone shares all of his work with everyone else. Nobody neds to reinvent the wheel, “we all stand on the shoulders of giants”.

            Creating a proprietary derivative is exactly the opposite: It is grave disrespect to the original authors.

            Nobody has contested that anyone can take the ETSI TETRA specifications and create a TETRA implementation that is independent from osom-tetra. But then in such an implementation, there obviously cannot be any code from osmo-tetra 😛

          • max

            Funny you discuss in riddles interlaced with your own biases that are ‘above the law’s or decency. Using Bitcoin to hide your true identity won’t work for long, eventually you will be identified.

            Can you kindly give a straight answer to questions put to you above.

            • moneriomaa

              it is funny really, i think you do not know anything about openear!
              else you must know that openear is free, paid version is only for decryption that there is no source code on net, This is unique, all challenges about tetra and open-source problem, not for paid version that works for decryption.
              there is no issue for owner decided sale his product in bitcoin, what is your problem with this?!!
              there is no illegal, there is many paid software for decryption you can find with search on net!
              there is no kindly for people that prevent others to use free softwares because they forced owners without kindly, and if you have little experience on programming and comint you can see that i answered all, i removed software please spend (waste) your time to challenging with others
              i unsubscribe this post to be free from some old-mind comments

    • moneriomaa

      on this link that you referred to it there is two challenge about PDW and telive!
      about PDW i share document that used on ads-b implementing ads-b is open documented and there is no secrets task!
      about telive there is also two notes, one i set link of etsi that anybody can download tetra vocoder code
      also code writer of telive emailed me after all dmca challenges and suggested to help if his codes is under challenge, but in fact there is no telive problem as i said vocoder code is on etsi and anybody can use it
      as i said i wrote openear 5 years ago (with simple UI) and use it individually but i decided to share it free for using by others!
      I think having it is better than not having it, and there is no force Lawyer-Engineer!

      • Lawyer-Engineer

        I think the problem is that you stated in public that “OpenEar is my try to improving current open source projects in github or other sources from any language to c++ for compiling on VC++“. So I take that to mean that you have rewritten open source code in another language aka a “port“. Doing this does not circumvent license laws! If you derive your work from another open source project, then your code must use a compatible license, it cannot be closed source. This is the law, there is no skirting around it.

        If you did actually rewrite everything from scratch from standards and books without using any open source code then I do congratulate you on your legal code. But the fact that you mentioned that you are just porting open source code has tainted you and brings everything into question.

        At my old workplace we did clean room design and rewrites – a legal way to rewrite code that is incompatible with the target license.

        • Slim Jim (no relation to fat Pat)

          My guess is that at a future date that someone will decompile your binaries and compare the data structures and exact order of processing in the algorithms used to the open source projects that you have erroneously claimed in public that can ignore their licenses “there is no rule that when you change open source, the result must be opensource”. There are loopholes, and that is the reason why the Affero General Public License was created, but your binary only distribution is not using any existing loophole. You have publicly admitted to breaking the law, by ignoring licenses multiple times.

        • moneriomaa

          although i have different opinion with you on this sentence “This is the law”
          when you talk about all world then the meaning of law maybe different, in this state you must see how is the “legislative” and “lawyer”,
          i think copy-left and around its licenses and laws has many big faults in behind of them!
          in many cases opensource is like trap
          there is many codes that i think those are unusable for many peoples only coders can run it on difficulty states, please note that we are talk about skills and experiences when some people has skills
          many peoples has not skills for compiling and using those scattered codes, i can write very complicated code and i can only run it then i share it like opensource code then i say anybody that use it then he must share this code! please note that this code unusable for porting in other project it needs many many changes and it far away from first code, ok then we has new code i can use it only by myself and nobody knows that there is easy decoder but also i can share it for using by other people!
          i select to share it with others! when i did not share it then you and other lawyers can not know how i did it! also You quoted my many old sentence on my GitHub i think You can not cite it because there is many changes and replacing on it, it is like that old man say sentences in childhood and after 70 years ones say that hey you said it….
          if i think people to bother me about replying to them, no problem i can easily remove this repo and use it by my-self next versions! i think it is maybe better for people that has free time to challenge, they can find another repo for challenge

            • moneriomaa

              it is like ones post multiple comment on this page with different names!
              please read all notes that i wrote before and check that all codes is different and notes that those codes authors is not creators of protocols and all documents is free on net, ok?
              i hope some one tries to decompile and shows ones like you
              really i bothered from answering for prove nothing! i don’t know if it is hard for you for using free exe software please use other Linux scattered codes
              also i guess you has not any view about programming and complexity, if you have this you can understand those codes is unusable for porting, if it is be easy or usable many exe files must be created! as i said those codes like trap, and know that coding systematic program is not easy task for be open-sourced
              anyway i have no free time for more answering to ones that has free time for challenging on nothing i decide to use it again individually and remove completely repo from GitHub
              also i use next version that contains more protocols individually and then no body like you can comment on this page

  2. Rob916

    Don’t let these people put you off.
    You have a lot of people following your project.
    Always politics that ruin things.
    Please keep up your good work.

    • moneriomaa

      thanks for your attention
      no problem for challenges
      as i said openear is for users not for developers
      i try to improve it more
      Best Regards

  3. test

    Grarme, talking about pseudonyms like ask, i only see your nickname? I think you like the have the source to use it for your self. This how it go in this community for 25 years. Using what others are making. I able to write a big book about this.

  4. Slim Jim (no relation to fat Pat)

    Any project that only uploads binary files to github, with no source code at all, nothing odd about that at all.

  5. Graeme

    App is as dodgey as they come. Hiding behind pseudonyms including business model and finding utilising Bitcoin. These types of activities are suspicious of black market operations of bad actors.

    • moneriomaa

      bad actors? ok scene for you and good actors, please play your role and do not conflict with others role! OpenEar is free program
      and only decryption is paid and decryption is not open source! decryption is paid because of complexity of codes and usage

        • moneriomaa

          as i said openear is free program to help users can listen to digital decoder easily in compare of some separated project and codes, paid version is decryption part, if you think it is stolen please reference me the source code that was stolen you can not find any source code on net about decryption! and how it can be stolen when it is not exist?!, i know that i developed and take long long hours for processing data and find decryption process and then it is only paid and related to bitcoin,
          there is many helpers that records for me dmr radios and i check them for finding way to decryption
          you do not know about that and only repeat some words! but it is not important for me

    • linux

      I be in this community from year 1997, For all these years there always be this type of coders. DSD asking money and the code is not open. What part you dont like?

  6. Harald Welte

    As openear was still using (slightly more obfuscated) OsmocomTETRA code without complying to its license (AGPLv3), it has been removed from github via a DMCA takedown request. The history of the repository and all of its forks on github have been removed.

    We at Osmocom are more than happy if people build on top of our open source code – but the license must be followed. We intentionally choose copyleft-type licenses for most of our code as we don’t want it to be used within proprietary programs.

    • moneriomaa

      congratulations! but you think wrong! openear never will be takedown! tetra is little part of openear, and temporality i removed exe for change and upload it again, currently users can’t use openear because of some unfair pressure but not important very soon completely tetra changed source and in continue never i wish write someone’s about osmocom, in old version demodulator completely changed, it cleared that osmocom used library but i wrote my own 8psk demodulator changed message decision to pi/4dqpsk and i only need voice traffic then in near future other remain part is completely will be changed
      and openear continues its ways

      • Bill Gates

        I wonder what other open source code open ear incorporates in it’s closed source code. Is every module stolen from somewhere else?

        • moneriomaa

          you said that every closed source program is stolen? good idea please let us know more, but in other view in my mind
          some open source code is like a trap, they can not be used commercially because they are not user friendly and need to put a amount of unusable (usable only for few number of people) code to access business codes and applications, ok i can not say them you’re welcome, i said them never you can find openear open-sourced, it is for users not for programmers

    • RF Guy

      Openear was a easy way to listen to TETRA on Windows. Please come back OpenEar !
      Maybe the Osmocom People can’t program on windows….

      • moneriomaa

        thanks for your attention, but as i said some ones think they creates tetra and any body forced to using their code! but don’t worry in near future i release some part of codes to they can see that tetra is free documented and other people also can writes code, they really bothered me, i don’t know i must take my time to prove them or add new protocols and features to openear

    • test

      Harold, like mention I be in this community from year 1997. I never read this kind of crab in last 25 years. TETRA is fully open protocol all the ETSI documunts are public domain. If you dont like people use or share or write sources, remove the whole code Osmo website pages. nobody able to use it anymore. BTW i did not hear any complains before ported code. Is your company broke due economic crisis what is the problem?

Post a comment

You may use the following HTML:
<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

This site uses Akismet to reduce spam. Learn how your comment data is processed.