Sabertooth DIP switch wizard
serial data

Serial control eh? You must be a pro.

You can choose between simplified serial mode, or packetized serial mode
Both modes can be used to control multiple Sabertooth boards.
Simplified mode is really easy to program, but will require many microcontroller pins to control many Saberteeth.
Packetized mode is a little harder to program, but is often the best choice for large networks of motors. 
This question affects switches 1 and 2.