My instructor said my homework is not in text mode. When I try to Attach a file or upload a file, I see characters on the screen and after a while I get a message saying it timed out. The BBS was waiting for you to start the UpLoad on your end. How this is done is dependent on YOUR software and YOUR software alone. I can only list software I have or get and have the time to evaluate.
Random characters appear intermittently on the screen.
If it is random and intermittent, then it is noise on the phone line. Menus on the BBS contain a lot of odd characters, and are very hard to read. These are ANSI control codes . Your communication software is set to Half Duplex. Just setup your communication software for Full Duplex.