Location. The card security code is typically the last three or four digits printed, not embossed like the card number, on the signature strip on the back of the card. On American Express cards, however, the card security code is the four digits printed (not embossed) on the front towards the right.
The CID/4DBC is ALWAYS located ABOVE the embossed (raised) account number on the face of the card. In some instances, the CID/4DBC is located on the left side of the card, but is always above the account number. Some cards have a four-digit number embossed below the account number, but this is not the CID/4DBC.