- What are Threema calls?
- What are the system requirements for Threema calls?
- How do I place a voice or a video call?
- How can I disable Threema calls?
- What is the bit rate of Threema calls?
- I hear my own voice as an echo – what can I do?
- How secure are Threema calls?
- Threema calls: What do those sounds mean?
- How do I adjust the image quality of video calls?
- Video transmission doesn’t work properly: What can I do?
- The connection can not be established. What can I do?
What are Threema calls?
Threema calls impress with crystal-clear voice quality and brilliant video quality. Since they are end-to-end encrypted, they are tap-proof. Instead of a phone number, the Threema ID serves as unique identifier.
- The call connection is established using Threema messages in the background; therefore, voice calls are just as trustworthy as chats, and the same verification levels apply
- If possible, a direct connection between caller and callee is established (peer to peer) after the connection buildup
- Calls with
verification level 1 (red) IDs are routed through the Threema server in order to obscure the IP address (in “Settings > Threema Calls,” there’s an option to route all calls through the Threema server)
- Because a constant bit rate is used for audio encoding, no conclusions about the content can be drawn from the size of the transmitted data packets
- Video transmission is an option of Threema calls that can be enabled at any time during an ongoing call. Once a Threema call is established, both parties can independently enable and disable video transmission by tapping the camera icon.
- Thanks to Threema’s contact verification, Man-in-the-Middle attacks can be effectively prevented, and there’s no need to manually verify a code for the purpose of authentication
For detailed technical information in regard to Threema calls’ security, please refer to the Cryptography Whitepaper.