The simplest way would be with the UNIX utility od (octal dump), which converts from binary to octal/hexadecimal/ASCII. It can also function as a filter program, so that, on UNIX systems, you can convert data streams in real time. od is standard on UNIX, and can be obtained as freeware for DOS/Windows.

However, DOS and Windows don't handle command pipes properly, requiring temporary files that are only processed after the input has stopped. That makes them generally unsuitable for real-time streaming. Not a problem if you're transferring later, after accumulating the data. But it sounds as if you're specifically dealing with real-time transfer.