Fax technology has existed for a very long time, the ability to send an image over a wire actually predates the invention of Alexander Graham Bell's telephone.
Shortly before World War II, in 1923 the Germans were using an early version of the fax machine called the phototeleautograph developed by Arthur Korn. It could send images such as fingerprints across the country.
Fax machines use data network.
Modern fax machines use scanned documents to transmit text.
Photocopiers, fax machines, franking machines, computers, coffee machines, shredders, scanners and others.
Voice
World War 1 saw the introduction of the tank and of aircraft.
Network-connectable fax machines can be obtained and function much like a network printer, with added input for recipient data. A networked fax machine will typically come with its own fax software for use by the client when sending a fax from their network.
Fax machines can be hooked up to your regular phone line. The disadvantage of this is that your line will be busy while sending or receiving a fax.
I used fax machines before, but it is very uncomfortable, now use <a href="http://www.popfax.com> Popfax </a> which is an internet fax and does not require a fax machine and it is much easier.
Most of today's fax machines have some sort of computer processor, which rely on mathematics.
Many people and companies still use fax machines. A great place to go to find out about the different brands would be a place like Staples or Office Depot.
This is not a straightly related answer but I would like to share my experience with fax machines. Fax machines have given me so much trouble instead of convenience in past so many years so I have switched to internet faxing. An internet fax can be accessed from anywhere within the world. Unlike fax machines, you can receive fax anytime of the day without having to worry about the location. This unique facility also lets you receive voicemail as email attachments and your service provider gives you space on their server to save your faxes online, thereby extending an opportunity to save the clutter on the desk.
The idea behind a virtual fax is to enable business to send email faxes without the use of a fax machine. This helps to reduce the cost for fax machines, fax services and long distance fees.