Hello, Ping.
The picture you posted is from the documentation for our older micro serial servo controller, so any serial commands documented in there will not work with the newer Maestros, like the Micro Maestro you are using. You can learn more about serial communication with the Maestro inside the “Serial Interface” section of the Maestro’s user’s guide, which you can find under the Resources tab of its product page. You might also consider getting started with this LabVIEW VI for the Micro Maestro, which was made by one of our customers. (However, please note that we do not use LabVIEW, so we do not know how well it works.)
The Maestros get processor power from the computer when connected over USB, so you do not need to separately connect power to the board in order for it to generate servo signals. (The servos still need to be powered, however, for them to respond to the servo signals.)
Setting the target to 0 on a Maestro will cause it to stop sending pulses to the servo. Most servos will stop trying to maintain their position if this happens. If you need more control over connecting/disconnecting power to your servo, you might consider adding an RC switch with a relay or MOSFET, which can be triggered with servo pulses generated by the Maestro.
-Jon