Apple Logic Pro 9 - Manual (Page 1082)

If the checkbox is not selected, the object and its icon will still appear in the Environment.
You should only select the Icon checkbox if the object will be used as a track destination.
Icon
Click the icon (next to the checkbox) in the Object Parameter box to choose an icon to
represent the object in the Environment and Arrange window track list.
Standard Instrument Objects
Logic Pro provides standard instrument objects to handle MIDI devices that only use one
MIDI channel (typically, older synthesizers, MIDI-controlled effect units, or drum machines).
Standard instruments transmit MIDI data on a single MIDI channel.
To create a standard instrument
Do one of the following:
µ
Choose New > Instrument (or use the New Standard Instrument key command).
µ
Click the Environment background with the Pencil tool.
The Standard Instrument Parameter Box
When a standard instrument is created, the following parameters are displayed in the
Object Parameter box.
• Port: Use to set a direct connection to one of your MIDI output ports. Remember that
you can also directly cable an instrument object to (or from) other Environment objects,
allowing MIDI processing.
1082 Chapter 37 Environment Objects Reference