With highly technical products usually you have at least two guys working on a account: The salesman, who deals with the business guys on the other side, the f

With highly technical products usually you have at least two guys working on a account: The salesman, who deals with the business guys on the other side, the folks who will actually sign the check. The sales engineer, that deal with the guys who will actually use the product, is able to understand their requirements and come up with ways the product can fullfil those, provide Proofs of Concept, demos and initial training for those guys on the other side that will give the final ok to the business people: 'this will work for us, you can sign the check if you want"