custom transfer function in flat file by using FTP

Hi,

     i want to use custom transfer function in flat file,i have seen .dat file in tec manual regarding custom transfer function as below

echo off

set USER=%1

set PASSWORD=%2

set LOCAL_DIR=%3

set FILE_NAME=%4

set LITERAL_HOST_NAME=%5

set INP_FILE=ftp.inp

echo %USER%>%INP_FILE%

echo %PASSWORD%>>%INP_FILE%

echo lcd %LOCAL_DIR%>>%INP_FILE%

echo get %FILE_NAME%>>%INP_FILE%

echo bye>>%INP_FILE%

ftp -s%INPT_FILE% %LITERAL_HOST_NAME%>ftp.out

please explain the above code and what changes i have to made to this code if i use FTP as custom transfer function