Note: If you are creating a custom gateway, see Creating a custom credit card gateway.
More:
Installing iMIS and adding license keys
AR/Cash Credit Card Authorization window
Setting up credit/debit card cash accounts in AR/Cash
Requiring a Card Security Code (CSC) for credit/debit card transactions
Accepting and validating Diners Club and Carte Blanche credit cards
Setting up multiple card authorization accounts
Setting up authorization options in Fundraising
Setting up European debit card authorization
Setting up an authorization account for non-iMIS supported gateway
Database schema for authorization and cash accounts