Thank you very much Eduardo! You are the first that gives me a possible technical explanation. McDonald's are in most cases wired with ADSL or faster connectio

Thank you very much Eduardo! You are the first that gives me a possible technical explanation. McDonald's are in most cases wired with ADSL or faster connection, since they serve free wifi in the store. I would guess they use the same connection for the POS. My two guesses were: 1) Fast connection with fast standard and maybe custom software to keep the channel open. 2) Pre-authorization, given the small sums paid and the low probability of frauds. I do also think that McDonald's might have a specific agreement with a gateway or a bank. They use Ingenico's POS, so I ruled out custom hardware. I will update the thread if I find anything interesting! Thank you again! Marco