if you find a barcode reader removed from equipment , most of them have built in circuitry and communicates through rs232 . you can easliy implement communication with mcu .
Try of using rs232 barcode scanner. RS232 barcode scanner sends data in ascii char,
pattern of data sends from rs232 barcode is
Start char(0x0h)+data+End char(0xDh).
Connection:
Barcode MCU
TX PIN RX PIN
GND GND
Write your program to start reads after detection of start char and stop read when detects end char.