Incoming data is sent 8 bits or 1 byte at a time. It arrives in binary there is no need to convert it, it arrives exactly as it is sent. However, you need to know what the sender meant by the bytes it is sending. At the end of the day all bytes are, are patterns of bits, these can be interpreted in an almost infinite number of ways. For example they could be simple numbers between 0 and 255, or signed numbers according to the ons'e complement or the two's complement system. They could represent alpha numeric symbols from a keyboard using the well known ASCII mapping of bit patterns to symbols. They can even represent a mores code pattern, in fact anything you can dream up.