Sends a file out through the COM1 port at 9600 baud. Handles both binary and ASCII files.
Prompts for the filename, and whether file is binary (as opposed to ASCII). If it is a binary file, it sends every byte with no changes. If it is an ASCII file, then it strips line feeds and the end-of-file marker, if any.
This is useful because some terminal emulators (such as PCPLUS on my XT)
have no convenient way to send a binary file with no error-correction
protocol, except by sending them as "plain ASCII".
But when sending plain ASCII, it treats some control characters specially.
For instance, if it encounters $1A (control-Z), it thinks that it
represents the end of the file, and stops there.
But when downloading a binary file to
COMM4, we want to
send every byte exactly as it occurs in the file, with no special
meaning or handling for any of them.