The PA-DSS Implementation Guide contains documentation for merchants, integrators and resellers to ensure PCI DSS compliance when using a PayEx terminal in a Point Of Sale environment.

Always follow the instructions given in the PA-DSS Implementation Guide and its supporting documents when integrating, installing or upgrading the PayEx Payment Application.

It is the merchant’s responsibility to comply with the guidelines given in the Implementation Guide. Neglecting these guidelines may result in a non-compliant PCI DSS environment.

PayEx strongly advices you to visit PCI's website for more information about security.  

You can find more about PCI DSS and SAQ documents on PCI's website here.