Two MIDI 2.0 devices reach full communication through an ordered discovery sequence ending in normal MIDI use

MIDI 2.0 brings two devices into communication through an ordered sequence. First connect and read transport-layer descriptors (name, connection info). Then, over a UMP-capable transport, run UMP Endpoint Discovery (learn supported UMP version, function-block count, device identity, and whether jitter-reduction timestamps are supported), Select Protocol (choose MIDI 1.0 vs 2.0 and set JR timestamps on/off), and Function Blocks Discovery (which blocks are active, their group membership and bidirectionality). Then MIDI-CI Discovery identifies devices by MUID and negotiates max SysEx size, after which MIDI-CI features (Profiles, Property Exchange, Process Inquiry) run, and finally normal MIDI messages flow. A device using only MIDI-CI over a MIDI 1.0 transport skips the UMP-endpoint, protocol-select, and function-block steps, because those messages require a UMP-capable transport.

Examples

A MIDI 2.0 interface links a keyboard to a DAW: endpoint discovery and protocol selection negotiate MIDI 2.0 and JR timestamps; MIDI-CI discovery and use exchange profiles and patch data; then playing sends channel voice messages.

Assessment

At which stage is it decided whether jitter-reduction timestamps are on, and which stages does a MIDI-CI-only device on a MIDI 1.0 transport skip, and why?