They're a code that you type in rather than a number to call. I really have no idea how they work, but I imagine they're some sort of non-text non-call sort of

They're a code that you type in rather than a number to call. I really have no idea how they work, but I imagine they're some sort of non-text non-call sort of thing? Don't really have anything sensible to google so I can't find out for sure. Hadn't thought of that though.