4. Fax

A Fax (short for facsimile) machine transmits a copy of written and graphical information via the telephone network.  It works in a similar way to a photocopier, except the copy is transmitted to a distant machine via the telephone network.

Each Fax machine has a telephone number, this may or may not be shared with a telephone.

Faxes are widely used in business offices because they make it very easy to transmit invoices, orders, rough drawings, copies of contracts and so on.

It is now possible to send and receive Faxes by email. The email is sent to a service company who then converts it to a normal Fax message and sends it to the telephone number you specify.

It also works the other way around, you can have a fax-to-email service where someone sends a fax in the usual way of calling a telephone number, but at the other end it get converted into a pdf (acrobat) document that is then forwarded to an email address.