SIP and XMPP support telling your peer that you're actually ringing at the user. In the XMPP case, this is distinct from acking the session-initiate: perhaps you're calling through an XMPP to POTS gateway. Currently, telepathy-sofiasip sends the ringing code (180) as soon as it gets an INVITE. I'm about to make Gabble do the same; longer term, we should support the UI saying it's ringing.
This is fixed in Call! Hooray.
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