Thank you Lars. What you’ve written was, I believe, copied verbatim from Cubasis 2 documentation, which I had read, and believed I understood. Having failed with Cubasis 2, in attempting to do what I have so often done with other midi master devices (synch external hardware drum modules connected as midi slaves to the tempo generated by the midi master), I presumed I had either misunderstood, or that your documentation was misrepresented, or there was a bug in this function known to you, but not to everyone.
My external hardware drum modules are configured to accept midi clock information. I have confirmed they work (start, stop, tempo lock) with a Boss RC-300 Loop Station acting as the master.
In Cubasis 2, I have opened a new project, created a new audio track, and selected “Send Midi Clock” in Settings/Midi. My iPad is connected to a Steinberg UR22 using the included cable and an Apple USB to Lightening adapter. The UR22 is powered by a separate 5V supply. A midi cable is connected from the UR22 Midi OUT to the Midi IN of a Boss DR880 drum module. The “Synch Mode” of the DR-880 is set to “Midi”. All the lights on the UR22 are correctly illuminated (no flashing). I confirm I am able to record audio through input 2 of the UR22, but the DR-880 is not responding to start/stop/tempo messages.
If you have any further advice or direction, I would be grateful.