In today's digital age, communication has become more convenient and efficient than ever before. However, there are still instances when physical documents or images need to be sent or received over a telephone or radio system. This process, known as faxing, has been a staple in many businesses and organizations for decades. But what exactly is used to send or receive printed text documents or images over a telephone or radio system?

The device used for sending and receiving faxed documents is called a fax machine. A fax machine works by scanning a physical document or image and then transmitting it over a telephone line to another fax machine. The receiving fax machine reprints the document or image on paper. In the past, fax machines were bulky pieces of equipment that required a dedicated phone line. However, with the advancement of technology, fax machines have become more compact and can now be integrated with multifunction printers and computers.

One of the key components of a fax machine is a modem. The modem converts the digital data from the scanned document into audio signals that can be transmitted over a phone line. The modem on the receiving end then converts these audio signals back into digital data, which is then printed out as a facsimile of the original document. Additionally, fax machines also have a document feeder that allows multiple pages to be scanned and transmitted in a single operation.

In recent years, with the rise of digital communication platforms, the use of fax machines has declined. However, they still remain a vital tool for industries such as healthcare, legal, and government where the transmission of sensitive information is required. In these sectors, faxing is preferred over email or other digital methods due to its perceived security and authenticity. As technology continues to evolve, there are now online fax services available that allow users to send and receive faxes via email or through a web portal.

Overall, fax machines have played a crucial role in the history of communication and continue to be relevant in certain industries today. While the technology may be considered outdated by some, there is still a need for physical document transmission in various sectors. As we move towards more digital and paperless workflows, the use of fax machines may continue to decline, but they will always have a place in the world of communication.