STEP 6 - Before we click on the Send button, verify that the serial port's speed is set to the correct baud rate for your setup. The normal default for an H8-5 Cassette/Serial board is 1200 baud. Verify that RealTerm is using 8-bits, no-parity and 1-stop bit (8N1).
Given the speed of modern computer serial ports, we also need to insert a small delay between each character (a.k.a byte) being sent. I found that 10mS is good for all possible forms of file transfer but you may wish to experiment to see what your system can get away with.
If all looks good we can send the file by clicking on the Send button.