How to Use the Merchant Direct Access Service

How to Use the Merchant Direct Access Service

The Merchant Direct Access Service (MDAS) provides Address Verification Service (AVS) authorization services to smaller merchants operating in a card-not-present environment, mainly to small mail order and telephone order (MO / TO) businesses. MDAS connects merchants to the AVS service by telephone. If your credit card processing volume is small or infrequent and if electronic access to AVS is not otherwise available, or if you want to access AVS for transactions that are key-entered when the card’s magnetic stripe cannot be read, MDAS may be the right option for you. MDAS provides AVS service on a per-transaction basis.

How to use MDAS. To use the Merchant Direct Access Service, all you need is a telephone and a Merchant Access Code (MAC) which you will get from your payment processing provider. To request an AVS authorization, you will dial a toll-free number and follow the instructions that the automated system will give you. You will need to provide your customer’s billing address and account number and the system will give you the verification results.

MDAS responses. The responses MDAS provides are very similar to the ones AVS provides but do not include response codes. You will receive one of the following MDAS responses:

MDAS Response


Exact Match

Both the street address and the ZIP code match. As far as AVS is concerned, the transaction is legitimate and the merchant can go on and process it.

Partial Match

The street address matches, but the ZIP code does not. This is a sign of a potential fraud and may warrant additional investigation, especially for larger transaction amounts.

Partial Match

The ZIP code matches, but the street address does not. Just as the other “Partial Match” result code, this is a sign for a potential fraud and additional investigation is advisable.

No Match

Neither the street address nor the ZIP code matches. This is a strong indicator of a potential fraud and you should investigate further.

Retry Later

The card issuer’s system may be down or it may not support AVS. You should resubmit your authorization request later.


It is an international address. AVS cannot verify international addresses, other than in the UK. You should take further investigative steps.

MDAS provides a way to use AVS on a selective basis. Merchants who choose to implement it will be able to cut costs by minimizing address verification requests, while still verifying the validity of these credit card transactions that are most likely to be fraudulent. If you choose to enroll in MDAS, you need to contact your processing bank.

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