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.
Re: efax supported printers. The HP Photosmart eStation C510 series printer faxes without a phone line. The printer sends and receives faxes using eFaxÂ®, a web-based faxing service. This service is free when you send up to 20 pages and receive up to 20 pages per month.