title: POS link payment integration in c# or Vb.net using pax devices
body: <p>Our payment processor has provided us with Semi-Integrated PAX S300 EMV Terminals. These terminals allow us to initiate an EMV/Mag/NFC Credit Card Transaction with just a few lines of code via the PAX POSLink DLLs. The terminals then take care of all of the processing and pass back a simple APPROVED or DENIED message to POS with some optional details like Authorization #, Batch #, etc. This would allow us to keep our POS system out of PCI Scope and EMV Compliant without having to pay for the extra fees associated with the Micros Payment Gateway and other similar services. </p>
  
  <p>We have a couple different approved register systems for our organization and the Micros 3700 System is currently our 2nd most used system but as we're not a Micros dealer, and dealers have no desire to help us accomplish this task, so we're trying to make due on our own without much access to documentation. I've found enough online to understand the basics and am trying to fill in the blanks, but any help would be greatly appreciated.</p>
  
  <p>Basically the goal is for the end result to function something like this:</p>
  
  <ol>
  <li>Cashier presses the SIM Tender Button</li>
  <li><p>SIM/PMS Interface Sends a message with the amount to VB.net App asking for approval.</p></li>
  <li><p>Vb.net App Maps the Micros Terminal to its corresponding PAX Terminal and Initalizes the PAX Terminal over IP (via the POSLink DLL) and waits for a response.</p></li>
  <li>Customer Swipes/Taps/Inserts Card</li>
  <li>Terminal Processes transaction and sends back Approved/Denied/Timeout/Error to the vb.net App</li>
  <li>VB.Net app translates the response into something the SIM can understand.</li>
  <li>Payment is either Applied to check, or not Applied to check depending on response.</li>
  </ol>