The OverrideAVSPolicy codes are 2 character codes which instruct the gateway how to handle the AVS checking for that particular transaction.

The first character determines the behaviour when 1 or more of the results of the address numeric or post code check are known.

The second and third characters determine the behaviour when dealing with partial matches – this is where either the address numeric check or the post code check returns partial matches.

The forth character determines the behaviour when none of the results of the address numeric or the post code check are known.