Xubuntu and callto/tel handler opens softphone but does not ring. Why?

Question

linux

Help please, killed 6 hours, I can not figure it out. Task: teach Chromium or Firefox in xubuntu 14.04 32bit to open tel or callto links in a softphone that calls them via sip.
Tried on Yate, Empathy, Jitsi, Linphone and SFLphone softphones. I found the corresponding file in /usr/share/applications/.desktop and added the %u parameter to exec.
Example: Exec=jitsi %u
I add lines to sudo nano /usr/share/applications/defaults.list

x-scheme-handler/callto=<appname>.desktop
x-scheme-handler/tel=<appname>.desktop

I do sudo update-desktop-database
As a result, I get that when I click on the link <a href="callto://[phone]">Звонить</a>
, the specified application just opens, but the call is not initialized. Even the number does not fall into the dialing field. I assume that some argument is simply not being passed somewhere. Maybe this is a feature of xubuntu?

Answer 1

Duc is the same old bike and Google for one and two