DCStart is similar to using the direct executable. 
DCStart.bat
                                        runs the appropriate DC_SYBASE.bat
                                file to ensure that all the appropriate Sybase-specific environment
                                variables are set. This is the required method to start a
                                DirectConnect server, for one or multiple versions, since ECDA no
                                longer sets the system environment.
 
Syntax
DCStart [direct executable
                Parameters]