Fax technology - fax machines, computer faxing, efax

Essentially, Fax machines  scan documents creating a digital image of that document in memory.
The digital image is then forwarded to the modem within the fax machine. Then the modem dials out
,using analogue technology to send out the document. The modem converts the digital image into
an analogue signal in order to transmit the document.

Generally, within the UK, most commercial phone lines use an analgue line to connect from the users
residence or office, to the main telephone trunk. The main telephone trunks usually digital lines,
carry phone signal all around the network

Once the destination number has been reached the digital image exits the main digital trunk, into
the analogue cable connecting the main telephone trunk to the fax recipients office or home. The
receiving device, usually another fax machine recives the analogue signal and converts it into a
digital output using its own modem, the resulting digital output can then be interpreted by the
fax machine an printed out as document.

Nowadays, fax capable devices come in different formats.

Basic fax devices: The usually consist of a phone and paper loading device, often, the fax machine
does duty as both voice communication phone and fax machine.

Multifunction devices: The fax machine here is embedded in a printer, copier, scanner device. These
devices can often be linked directly to a network.