"Fax Machines"[img]2012q1/ct_etoefm_etoefspeakc_1738_20121[/img] Now listen

Narrator 2: Number 6. Listen to part of a lecture. Then listen for a question about it. After you hear the question, you have 20 seconds to prepare, and 60 seconds to record your answer.
Narrator 1 : Now listen to part of a lecture in a business class. The professor is discussing the way that a fax machine transmits and receives data.
Professor:
    Okay, to illustrate my point that many new machines are simply combinations of machines that are already available, let’s talk about the fax machine. To understand how a fax machine works, I’d like you to think of it as three machines.., a copier, a modem, and a printer. First, the data is copied. How does that happen? Well, when you load paper into the fax machine, a light shines on it and optical sensors read whether a specific point on the paper is black or white. These sensors communicate the digital information into a microprocessor, where a copy of the page is made of black or white dots. Thus, you see that in the first step, the fax machine functions like a copier. Next, the fax machine works like a modem. Remember, a modem takes a black-and-white image and converts this digital data into an analog signal, that is, electronic impulses that can be sent over a phone line. The fax machine calls another fax machine to transmit, using two different types of tones to represent the black and white dots in the document. For example, it might send an 800-Hertz tone for white and a 1,300-Hertz tone for black. The last part of a fax machine is the printer. After the receiving fax machine answers the sending fax machine, it begins to accept the electronic impulses, and then it converts them back to the black-and-white dots in a digital image. Finally, it prints the image out on paper just like any other printer.
Narrator 1: Using the main points and examples from the lecture, describe the three parts of a fax machine and then explain how the fax process works. Narrator 2: Please prepare your answer after the beep.
Beep
[Preparation time: 20 seconds]
Narrator 2: Please begin speaking after the beep.
Beep
[Recording time: 60 seconds]
Beep