For all of you, I connected my TI-74 to my computer to save the basic programs and to load new ones. I used the https://petlibrary.tripod.com/cassette.html to create a cassette device or using the Arduino Leonardo (https://github.com/molleraj/ti95interface). I have created a Python sofware to to manage the full process, take a look at https://github.com/rinxo/TI74-Manager.