Requirement 9 focuses on restricting physical access to sensitive areas like the data center, workstations, and printers in the Cardholder Data Environment. It requires monitoring access through cameras or controls, retention of data for three months, restricting public network jack access, controlling physical access with badges, revoking access upon separation, implementing visitor management, and properly managing devices storing electronic media. The requirement also stresses the protection of POI devices from tampering to prevent skimming incidents, and it highlights common challenges during assessments like not considering paper-based data, overlooking metal universal keys, lacking exit access controls, inadequate camera data retention, incomplete visitor logs, and more
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