The necessity of a traditional telephone connection for facsimile devices is a common inquiry when considering the operation of such equipment. The mechanism through which these machines transmit and receive documents was historically dependent on the public switched telephone network (PSTN). The fundamental principle involves the conversion of a physical document into an electronic signal, which is then transmitted over the phone line to a receiving machine that reconstructs the document.
The dependence on a physical phone line has dictated the deployment and accessibility of facsimile technology for many years. The ubiquitous nature of landline phones meant facsimile machines enjoyed widespread adoption in businesses and homes. This reliance, however, presented limitations, particularly in areas with unreliable or limited phone service. Furthermore, the cost associated with maintaining a dedicated phone line specifically for fax transmission added to the operational expenses.