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.
If the fax machine has a small display screen, look for a confirmation that the fax went through. Some fax machines will also print out a short confirmation report. Here's how to receive a fax: 1  Make sure the fax machine is plugged in, powered on and connected to a working phone jack.2  This phone jack can either be your regular phone line or a dedicated fax line.3  The important thing is that the sender has the right number. Gather the documents you want to send and put them in the order you want them to be received. 2  Fill out a separate piece of paper called a coversheet with the recipient's name, fax number/phone number, your name, your phone number, a short message and number of pages (including coversheet).