1. Download the [[https://linphone.org/releases/linux/latest_app|Linphone AppImage]] from [[https://www.linphone.org/|Linphone]] and make the file executable (e.g. "chmod +x Linphone-*.AppImage") 2. After the first start you must accept the terms of use and privacy policy of the Belledonne Communications (developer of Linphone) {{:linphone_linux:linphone_linux_01w.png?direct&400|}} 3. Start the SIP configuration with the highlighted button " USE A SIP ACCOUNT" {{:linphone_linux:linphone_linux_02w.png?direct&400|}} 4. Accept the "limitation" with "I UNDERSTAND" {{:linphone_linux:linphone_linux_03w.png?direct&400|}} 5. Add the SIP credentials and server which you get in the [[https://guru3.eventphone.de/event.wasm/phonebook|guru3]] behind the key sign and set the transport protocol to "UDP". You confirm the configuration with "USE". {{:linphone_linux:linphone_linux_05w.png?direct&400|}} 6. If you configured correctly you should see a green checkmark next to the display name and the user SIP uri. {{:linphone_linux:linphone_linux_06w.png?direct&400|}} 7. Test the SIP registration with a call to ERNA (**E**igene **R**uf**N**ummern **A**nsage) extension 8330 {{:linphone_linux:linphone_linux_07w.png?direct&400|}} 8. The call should be established and you see the call screen. You should hear your own extension if all is working {{:linphone_linux:linphone_linux_08w.png?direct&400|}} 9. In the call list you see all incoming and outgoing calls {{:linphone_linux:linphone_linux_09w.png?direct&400|}} 10. At the top right you have a dial pad {{:linphone_linux:linphone_linux_11w.png?direct&400|}} 11. You can add additional SIP accounts via the gear and choose "Preferences" {{:linphone_linux:linphone_linux_12w.png?direct&400|}} 12. At the bottom right you start the configuration for additional SIP accounts via "ADD ACCOUNT" {{:linphone_linux:linphone_linux_13w.png?direct&400|}} 13. Add the SIP credentials to the ... {{:linphone_linux:linphone_linux_14w.png?direct&400|}} 14. {{:linphone_linux:linphone_linux_17w.png?direct&400|}} 15. {{:linphone_linux:linphone_linux_18w.png?direct&400|}} **Special configuration** Under Preferences → Calls and Chat, “Encryption” needs to be set to “None”. Similarly, under Preferences → Network, “DTMFs sending method” needs to be set to “SIP INFO” for the labyrinth to work.