This is one of the positions that have a direct line of communication with your customers. These individuals answer product related questions, up-sale and perform other related duties for your company.
These individuals are not technical and simply help customers in the ways of using your products and getting the most out of them.
However, the more customer service calls your company receives is typically an indication of how user friendly your products are to begin with. Better designed and manufactured products require less assistance to operate.
The purchaser role is designed to analyze the market for materials to be used for product design and also any purchasing process related to equipment for your company. This also includes services.
A good purchaser will maximize the value of each currency unit spent.