The Physical Input object represents the physical inputs of your MIDI interface. You can only have one of these objects in the Environment.
The Physical Input object receives MIDI signals from the inputs of the MIDI interface(s) connected to your computer. This object has a total of 65 outputs.
The outputs follow the input assignment of all connected MIDI interfaces. The top output (SUM) carries the MIDI events for all individual outputs that are not cabled separately.
Remote control events are intercepted at the Physical Input object, and are not passed through to its outputs. Because of this interception, remote control events will not reach the Environment, or be recorded on Arrange window tracks.
Choose New > Physical Input.
To make use of an existing object, drag it onto the relevant layer. This does not affect its cabling.