I haven't tried it myself but according to the FAQ:

"Jitsi offers a telephony interface that allows users to dial into a conference or for placing dial-out reminder calls. You can try this for free on meet.jit.si. Self-installed Jitsi Meet deployments will need to setup and configure Jigasi with a SIP provider to connect to the phone network. "

https://jitsi.org/user-faq/

Yes, you can deploy Jigasi (https://github.com/jitsi/jigasi) to VoIP access to Jitsi Meet.

if you go to the jitsi.org site and start a meeting, there is a share box that can be popped up and it shows a dial-in number for your conf. So it must have sip integration.