What do mean one-way and 2-way ? This is how much volume it can handle ? Maybe this is about security ?
This is kind of standard terminology:
- one-way are those machines that capable only of selling bitcoins to users (support "one way" only)
- two-way are those which allow to buy bitcoins and also sell bitcoins.
Currently in the world the split is
40% two-way vs. 60% one-way bitcoin ATMs.