Sometimes the temperature does not decrease with height in the troposphere, but increases. Such a situation is known as a temperature inversion. Temperature inversions limit or prevent the vertical mixing of air.
Middle range machines can cost on average $400 and are often multi-function with copier and laser printer capabilities. Finally, high-end machines which offer high speeds, high capacity and high resolution come at a higher price-expect to pay $1000 - $2500 for such a fax machine.
17. Other Output Devices. A fax machine or facsimile is a device that codes and encodes documents so they can be transmitted over telephone lines. Many computers include fax capability by using a fax modem. A fax modem transmits computer-prepared documents such as a word processing letter or document that has been digitized with a scanner or digital camera.