Interac is a payment method that combines all the major Canadian banks and provides one seamless interface between all the major banks in Canada as well as the many smaller ones like Simplii and Tangerine for example. There are over 80 Canadian banks that are connected to the Interac network. Of course, the 5 major Canadian banks that are connected to Interac are TD, BMO, CIBC, RoyalBank, and Scotiabank.
Email money transfer using Interac
The way Interac works when it comes to online gambling is you can send an eTransfer where you email money from one person to another. In this case, there is nothing for a user to tap because they are doing all their online gambling, well, online! Unlike a gas station, a store, or anything else you would tap a payment terminal (or POS) to pay for anything. Typically Interac allows users to tap for a $100 deposit. When it comes to Interac e-transfers, these amounts can be locked at $3000 per month. Limits for users can be increased but that depends on how cooperative your bank will be and that might relate to how much money you have in your account, your credit rating, and how long you have been banking with your bank.
If you really want to know everything about Interac, check out the Interac Wikipedia page.