I have no result found from Google regarding Designsync dword and i think i should share it out after getting the info from Designsync support.
grep -H ServerMaintenanceMode=dword:1 /<path>/<port_number>/PortRegistry.reg
dword:1 = Normal operation
dword:2 = Set server to read-only mode
dword:3 = block all read and write access to server