You can register Signal using a landline number. In this case, you need to follow the procedure below:
- Install https://github.com/AsamK/signal-cli
- Attempt a SMS verification process first (
signal-cli -a PHONENUMBER register). You might get an error400 (InvalidTransportModeException), this is normal.
- At this point, and especially if you are on a VPN, you might get an error message saying
Captcha required for verification. If so, go to https://signalcaptchas.org/registration/generate.html.
-
After filling the captcha, the site doesn't immediately show the token but tries to redirect to a
signalcaptcha://url that contains the token. -
After a short moment, a link will appear underneath the captcha called "Open Signal". Get the token by right clicking on it and clicking: copy url. You can paste that directly into
signal-cli -u PHONENUMBER register --captcha CAPTCHACOPIEDURL
It should now register. Remember that the captcha has to be pretty fresh