These are the ones I use, they're widely available, if you look at:-
https://www.ebay.co.uk/sch/i.html?_f...68249&_sacat=0
you'll see its a typical CH360G board.
Re the handshaking, back in the DOS days we used Procomm and Telix, either of which allowed you to write a script that sent a line, waited for the ">" prompt from NIBL, then looped until done. Don't think Teraterm does that?
That's progress...