The requirement of a dedicated analog connection for facsimile transmission has evolved significantly with technological advancements. Traditionally, sending documents required a physical connection to a public switched telephone network (PSTN). This involved converting document images into audio signals transmitted over the network, demanding a direct link for both sending and receiving. A common example involved plugging a fax machine into a standard wall jack associated with residential or business telephone service.
The reliance on a physical phone line presented limitations in terms of accessibility and infrastructure needs. Businesses and individuals needed to maintain active telephone subscriptions, adding to operational costs. Moreover, mobility was restricted as facsimile machines were tethered to a specific location. The historical context underscores a significant shift from hardware-dependent communication to more flexible, software-driven solutions that leverage internet protocols.