Fax hard to operate. In 1966, Xerox released the Magnafax Telecopiers, a smaller, 46-pound facsimile machine. This unit was far easier to operate and could be connected to any standard telephone line. This machine was capable of transmitting a letter-sized document in about six minutes. The first sub-minute, digital fax machine was developed by Dacom, which built on digital data compression technology originally developed at Lockheed for satellite communication. By the late 1970s, many companies around the world (especially Japanese firms) had entered the fax market. Very shortly after this, a new wave of more compact, faster and efficient fax machines
Fax to the e-mail to fax service that still uses fax modems at least one way. Computer modems are often designated by a particular fax class, which indicates how much processing is offloaded from the computer's CPU to the fax modem. Several different telephone line modulation techniques are used by fax machines. They are negotiated during the fax-modem handshake, and the fax devices will use the highest data rate that both fax devices support, usually a minimum of 14.4 kbit/s for Group 3 fax. Note that "Super Group 3" faxes use V.34bis modulation that allows a data rate of up to