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.
Sending a fax: 1  Make sure the fax machine is plugged into a power source and also plugged into a working phone jack. 2  Turn the fax machine on. 3  Obtain the fax number of the destination fax machine.  Gather the documents you want to send and put them in the order you want them to be received.