This is an important idea in PCI, and one that you need to understand. The Payment Card Environment is that part of your computer network that possesses cardholder data or sensitive authentication data, and those systems and segments that directly attach or support cardholder processing, storage, or transmission. For example, if you have a computer directly connected to a Point of Sale terminal, that computer is part of the payment card environment, no matter what you do (or do not do) on that computer.

The scope of the Payment Card Environment may be limited through the use of proper network segmentation.