What Does the POS Software Do?

We''ll use IBM''s eTill as one example of how POS systems operate within a Merchant Server. Figure 10.1 illustrates message flows and component interaction. eTill itself consists of the following components:

• A Java application receives messages from both Cardholders and Payment Gateways and sends messages to Payment Gateways.
• The C API Library permits access by any Merchant Server software that''s written in C or C++.
• The C Modifiable User Exit Shared Library enables the implementation of optional user exits or callback functions to dynamically retrieve information while a transaction is in process.
• Configuration databases are used to customize the system for flexible access to Payment Gateways and other applications.
• Transaction databases maintain information about orders and SET transactions.
• Sample browser-based forms enable further customization of configuration, administration, reporting, and message generation user interfaces.
• Certificate Registration Utility is used to obtain Merchant Certificates. eTill uses Configuration Profiles for the installation itself, the SET components, the Payment System configuration, the Acquirer(s) configuration, the Brand(s) configuration, and Acquirer Off-days configurations.

Specific installation and testing procedures can be found in Chapter 16, but it''s important to realize that there may be significant programming efforts required to interface with Merchant Servers and back-office accounting systems before you''re ready to accept payment cards via the Internet. Unless you''re starting from scratch with a complete turnkey solution, count on significant development work by your staff or someone you hire to perform it.