Question: how online checker works?

[Blackwood]

The Checker works like this, User interface--> Merchant --> Back to user Interface. What that means that all these checkers are using merchants to do small transactions, they find a merchant that needs only front of the card and Expiry which can be found in the track. The on hold transactions are called a Pre-Authorization and no, the card holder can still see them in the online banking, once the money is returned the transaction goes away from online banking. Hope this helps, Cheers !!!