Final answer:
The office instrument designed for sending and receiving printed documents via telephone is the Fax Machine. This electronic device scans, sends, and receives documents as audio tones over telephone lines, which are then reconstructed into images by the receiving fax machine.
Step-by-step explanation:
A fax machine, or facsimile machine, is an electronic device that sends and receives printed pages or images over telephone lines. The process involves scanning a document, converting it into a bitmap, and then transmitting it as audio frequency tones that are received by another fax machine. This receiving fax machine interprets the tones, reconstructing them into a duplicate image of the original page. This technology was vital for business communications before the advent of digital communication alternatives.
Although less commonly used in modern times, fax machines are still utilized in various industries, especially where legal signatures on documents are required. Fax machines are unique because they can send exact copies of original documents quickly and with legal recognition. Despite the rise of email and other digital methods, some businesses and organizations continue to rely on fax machines for secure document transmission.