To whom does the PCI regulations apply?
The PCI DSS standards apply to all entities that process, store or transmit cardholder data. This includes all merchants and service providers with external-facing IP addresses handle, store or transmit credit card data. Even if your website does not offer website based transactions (for example, you link to a payment gateway) there are other services that may make card data accessible. Basic functions such as e-mail and employee Internet access will result in the Internet accessibility of a company's network. These seemingly insignificant paths to and from the Internet can provide unprotected pathways into merchant and service provider systems if not properly controlled.