These are very crude modules - so you're (probably) going to have to implement your own scheme to cope with interference, etc.

You might also find that you have to use stuff like Manchester encoding to avoid "upsetting" them...

Yes, you can get modules that do all this for you, and look just like a MAX232 - but, of course, they are more expensive.

As ever, the choice is whether to save cash at the expense of your time & effort, or to save your time & effort at the expense of cash.