Was just on the phone with a business client who was having no luck trying to patch in a remote colleague. I was using Jitsi desktop client and noticed the "head with plus symbol" button. "Let me try", I said... and it just worked!

I use Jitsi for most of my work calls, via a SIP account from my ISP that connects me to the phone system. That's nothing new of course, but it is an arrangement that works really well for me.