How to install Signal on Desktop without smartphone but with old phone or landline

  • Install Signal for Desktop.
  • When you open Signal, you’ll be asked to Link your phone to Signal Desktop and there will be QR code. Take a screenshot of this QR code and save is as a file. Keep your Signal app open all the time.
  • Decode QR code using some tool i.e. qreader.online. You should obtain tsdevice URI which looks like this:
    tsdevice:/?uuid=1111111111111&pub_key=111111111111111111111.
  • If you have Docker installed on your machine you can execute below commands in the terminal on your local machine. Otherwise you can use some online tools like katacoda.com/courses/ubuntu/playground (without login) or labs.play-with-docker.com (Docker account required) or something else.
  • Start Ubuntu instance.
docker run --rm -it ubuntu:latest /bin/bash
Code language: Bash (bash)
export DEBIAN_FRONTEND=noninteractive && apt update && apt install -y openjdk-16-jdk-headless && apt install -y wget && wget https://github.com/AsamK/signal-cli/releases/download/v0.7.2/signal-cli-0.7.2.tar.gz && tar -zxvf signal-cli-0.7.2.tar.gz && cd signal-cli-0.7.2/bin
Code language: Bash (bash)
  • Don’t forget to replace +447777777777 with your number.
export NUMBER=+447777777777 ./signal-cli -u $NUMBER register
Code language: Bash (bash)
  • If it’s mobile number you should receive sms saying SIGNAL: Your code is 111-111. Otherwise (if it’s landline) you’ll get a call. Replace 111-111 with your code below.
./signal-cli -u $NUMBER verify 111-111
Code language: Bash (bash)
  • Finally you’re ready to link your Desktop app. Don’t forget to replace tsdevice URI with the one you obtained from your QR code.
./signal-cli -u $NUMBER addDevice --uri "tsdevice:/?uuid=1111111111111&pub_key=111111111111111111111"
Code language: Bash (bash)
  • Happy days! Your app should be linked!
  • Environmental cleanup
rm ~/.local/share/signal-cli/data/$NUMBER exit
Code language: Bash (bash)

All done!

5 thoughts on “How to install Signal on Desktop without smartphone but with old phone or landline

  1. When I try to register the number I get an error: ‘Captcha invalid or required for verification (null)” .. so what now?

  2. Hello, thank you for this tutorial, but some steps does not work for me :
    .
    I can’t use Katacoda without login.
    .
    If I use Katacoda, then I can’t install openjdk-16-jdk-headless.
    I can only install an old version, like openjdk-9-jdk-headless,
    but with an old version, the `signal-cli` script does not work.
    .
    Ok, it does not matter, I have Ubuntu on my computer.
    I can install `openjdk-16-jdk-headless` on it.
    The `signal-cli` script does no longer give me the same error… but a new one :
    “Captcha invalid or required for verification (null)”
    (note that I get this error only with a valid phone number, else it’s like
    “Invalid username (phone number), make sure you include the country code.”).
    .
    I see no solution for this issue, and 2 persons here having a similar issue
    (Dee [2022-02-27] and SW [2022-03-13 (today)]).
    .
    I searched a solution on several tutorials, tried several times, asked it to several persons, searched it on Google, DDG, YouTube, Github, Matrix, and found no solution. Am I really incredibly bad at searching ? Or is this solution simply obsolete ? Or something else ?

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