Is the word fax a common or proper noun?

The noun "fax" (short for facsimile) is a common noun, a general Word for a type of electronic device; a general Word for an electronically transmitted document; a Word for any fax of any kind.

A proper noun is the name or title of a specific person, place, or thing; for example, the Brother FAX-2840 High Speed Mono Laser Fax Machine or the Panasonic KX-FL421 Laser Fax Machine.

The Word "fax" is also a verb: fax, faxes, faxing, faxed.