While this may not sound important - it is when looking for a point of sale company that provides complete point of sale solutions that include the ability to process payments made by debit and credit card. In fact, VISA has mandated that all level 4 merchants need to have a "Qualified Install" done for any payment applications. In other words a QIR certified individual must perform the installation (or update) of any PA-DSS compliant payment applications. This is to ensure the installation and configuration of the application is done in a PCI complain manner.
I'd recommend that you check to ensure that your point of sale VAR/Dealer/Partner has achieved the same level of qualification. From a security stand point, this would be a "best practice" when working with a business for point of sale equipment. Here are the websites that allow you to search to see if the company that you are, or will be working with, has the mandated certification:
As always, contact me at 208-340-5632 or firstname.lastname@example.org with any questions.