Cookbook Connecting Secondary Command Source - DCC-EX/CommandStation-EX GitHub Wiki

You may need this if you are implementing a separate throttle interface which sends JMRI-like DCC++ throttle commands <t> <f> etc. You can create additional serial inputs (reading JMRI like commands) by adding a line to your configure.h file

#define SERIAL1_COMMANDS

You may also use SERIAL2 and 3. Each serial used will automatically be set to a baud rate of 115200.