Read barcodes with different lengths and types

Hello,

I have a retail client that receives items from many suppliers. They want to use the barcode that the vendor has already placed on it, but the POS vendor says their system can only read one type of barcode at a time. So they would need to re program the system to scan parts from the different vendors. I assume this is because some are probably type UPC and other type code 39. Any ideas on a way to allow them to scan about anything without re-programming?

Thanks
Ray