1 converts written data into sound waves. 2  converts the sound waves from a voice into a digital signal. 3  converts letters from the keyboard into digital format. 4  converts digital sound waves into analog sound waves.
Travel agencies make their money in a variety of ways. The products agents sell have built-in fees that result in a profit for the agency. The amount of the fees and the ways in which they are earned and distributed differ by the type of product sold and the suppliers who provide that product to the agency.
A service fee was implement to compensate for the loss of commission from the airlines. Corporate travel agencies book the air/car/hotel for business travelers. They make money mainly off service fees, airline commissions in certain classes of service or on certain routings, and net/private fares. Corporate travel agencies also make money on hotel and car commissions.