This is a good and relevant question because the Task scheduler help is not finished yet.
The Magic RDS 4 supports several communication protocols and multiple connections. On the other side, it supports common control as well. As the result, is uses common ASCII equivalent commands for all models incl. UECP.
In your example (Data set change to 2) type following as the Task line:
send connection:"*" command:"PROGRAM=2"
This command will be translated to appropriate protocol for each connection (encoder). For the UECP, the output will be
<FE><00><00><00><02><1C><02><F9><D3><FF>
that's effectively MEC 1C ("Data set select") with value of 0x02.
You may specify Encoder address and Site address as well:
send connection:"*" command:"PROGRAM=2" adr:3 site:4
or if you want to send that to a specific connection (not to all):
send connection:"connection_name" command:"PROGRAM=2"
etc.
Complete list of commands is now available in the Terminal window under the "Set" button on the left side. We accept feature requests for the Task scheduler.