What Audio/MIDI Interface are you using with your Mac?
You can either go from the MIDI Out on the Tyros to your Audio/MIDI Interface, or you can go from the USB-To-Host port on the Tyros to a USB port on your Mac.
Take a look at the following articles on how to setup an external MIDI device in Logic:
[url]http://www.macprovideo.com/hub/logic-pro/setting-up-external-instruments-in-logic-part-2[/url]. This article is a bit more advanced and shows you how to incorporate Logic's Environment into the MIDI setup. This will give you more control and access to the synth. Such as being able to switch between different programs and parameters via Logic.
An excellent tutorial to watch on External MIDI devices and MIDI flow is Peter Schwartz's MIDI 101: