Fax machines allow for documents to be electronically transmitted over telephone lines, providing a faster alternative to postal mail. The idea for fax technology was conceived in 1843, but the first fax machine was not created until 1861 by Giovanni Caselli. Throughout the 20th century, fax machines became smaller, faster, and added color capabilities. Modern fax machines use optical scanning and laser printing to quickly send documents electronically in a variety of paper sizes.