Following is the ldt command used to download menu entry. This also downloads function so, need to download function separately.
FNDLOAD apps/<password> 0 Y DOWNLOAD $FND_TOP/patch/115/import/afsload.lct <ldt file name>.ldt MENU ENTRY PARENT_MENU_NAME='Menu Name' FUNCTION_NAME='Function Name'
For Upload
FNDLOAD apps/<PWD> 0 Y UPLOAD $FND_TOP/patch/115/import/afsload.lct <LDT_FILE_NAME>.ldt
FNDLOAD apps/<password> 0 Y DOWNLOAD $FND_TOP/patch/115/import/afsload.lct <ldt file name>.ldt MENU ENTRY PARENT_MENU_NAME='Menu Name' FUNCTION_NAME='Function Name'
For Upload
FNDLOAD apps/<PWD> 0 Y UPLOAD $FND_TOP/patch/115/import/afsload.lct <LDT_FILE_NAME>.ldt