This document describes conventions for using MIDI to generate tones on SIP UAs. This does not define any changes to SIP but describes how to use the existing Alert-Info header to play tones that can be used to indicate specialized PSTN tones such as the ringback tones from various countries. The tones are described using MIDI which results in a compact representation that is simple for a UA to generate and easy to render into audio. This work is being discussed on the sipping@ietf.org mailing list. This draft was revived at request of a few people so it could be discussed. Parts of it need to be updated since it was written in 2003.