[Operators] Protocol agnostic URI for voice or video call?

[Daniel Pocock]

RFC 3860 defines the im: URI prefix for a chat contact who can be reached using more than one protocol (e.g. both xmpp: and sip: URIs can be derived from the im: URI)

However, im: implies text chat only.  Are there equivalent prefixes to suggest voice and/or video sessions, and is there any generic prefix to suggest any arbitrary possibility (including smtp) at the caller's discretion?

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.jabber.org/pipermail/operators/attachments/20130107/688e40fa/attachment.html>