Checking Account Verification Systems
The ACH or echeck world does not have an authorization component as with credit cards. When processing credit cards you are able to authorize at the time of payment that the customer has the funds available on their cards. Most importantly you are able to reserve those funds for capture and settlement. So you know you are getting paid at the point of sale.
For some businesses this lack of an authorization means that a Checking Account Verification system to mitigate payment acceptance risk must be put in place.