[amyames]

Linphone works good for internal use and is free to other linphone users.

The drawback is that unless you can in a newer version, you must choose between using your free linphone video messenger account OR your external sip account that can do landlines.

Having mentioned both in this thread: my small business is using grandstream phones that receive calls on twilio [because it’s the only one that will ring up to 10 extensions on a single login], and then competitively make outbound on all the others I mentioned based on dialing patterns.

And then we use linphone for internal video, since we’re a Linux shop and teams is out. [it’s wonderful but just exasperating that I can’t configure a second account and use it for everything.]

Linphone otoh will call a proper SIP address for free, eg ourtelephonenumber@twilio or [e-mail] so I can conference in Cisco tandbergs, or I can conference in someone on one of the grandstreams that way. [when linphone is configured as a linphone rather than a SIP phone]