Parameters:

/InFile          Input file name, e.g. D:\DWGs\Building.dwg
/OutFile        Output file name, e.g. D:\DXFs\Building.dxf
/OutVer        Output file version, available values:
                   acad2018, acad2013, acad2010, acad2007, acad2004, acad2000, acad14, acad13, acad12, acad10, acad9, acad26, and acad25.
                   Default is acad2000
/BinDXF       Output binary DXF
/Hide            Hide the result window

Example:

Convert sample.dwg to sample.dxf
dd.exe /InFile D:\sample.dwg /OutFile E:\sample.dxf /OutVer acad2004

Convert sample.dxf to sample.dwg
dd.exe /InFile D:\sample.dxf /OutFile E:\sample.dwg /OutVer acad2000

Parameters:

/InFolder          Input folder name, e.g. D:\DWGs
/OutFolder        Output folder name, e.g. D:\DXFs
/IncSubFolder   Include subdirectories
/ConvertType   Conversion type, available values:
                       DWG2DXF         Convert all DWG files to DXF files
                       DXF2DWG         Convert all DXF files to DWG files
                       ALL2DXF           Convert all DWG and DXF files to DWG files
                       ALL2DWG          Convert all DWG and DXF files to DXF files
                       VERSION           File version conversion
/OutVer            Output file version, available values:
                       acad2018, acad2013, acad2010, acad2007, acad2004, acad2000, acad14, acad13, acad12, acad10, acad9, acad26, and acad25.
                       Default is acad2000
/BinDXF          Output binary DXF
/Hide               Hide the result window

Example:

Convert all dwg files to dxf files
dd.exe /InFolder D:\Drawings\ /OutFolder F:\Drawings\ /ConvertType DWG2DXF /IncSubFolder

Convert all dwg and dxf files to dwg files
dd.exe /InFolder D:\Drawings\ /OutFolder F:\Drawings\ /ConvertType ALL2DWG /IncSubFolder

Version conversion
dd.exe /InFolder D:\Drawings\ /OutFolder F:\Drawings\ /ConvertType VERSION /IncSubFolder /OutVer acad2000