, or 120 letters a minute. The first words sent over the telegraph, by inventor Morse himself, were "What has God wrought!" (I have since wondered what Morse, who basically invented a simple dot-dash sending system, would have said about, oh, say, a nuclear bomb.) The Telephone The telephone was invented in 1876 by Alexander Graham Bell, whose first words on the phone were, "Mr. Watson, come at once, I need you." Alex had just spilled battery acid down his pants and, as you can imagine, was in quite urgent need of his assistant's help. Figure 1.4 shows an illustration of two people, who Introducing Telecommunications we'll call Carl and Monica, using the telephone. What follows is a wordy description of how the telephone works. Refer to Figure 1.4 to help you with the terms. The transmitter consists of Monica (who is talking) and the transmitting (bottom) end of the telephone. Monica speaks, and her vocal cords vibrate. This causes vibra- tions in the air, which travel through and out her mouth, and then travel to the bottom end of the telephone. Inside the bottom end of the telephone is a diaphragm. When the vibrations of the air arrive at this diaphragm, it, like an eardrum, begins to vibrate. Directly behind the diaphragm are a bunch of carbon granules. These gran- ules are part of an electrical circuit, which consists of a 4-V source, copper wire, and the carbon granules. The carbon granules act as a resistor (with variable resistance) in the circuit. When the diaphragm is pushed back by the vibrating air, it causes the carbon granules (right behind it) to mush together. In this case, the granules act like a low-resistance resistor in the circuit. Hence, the current flowing though the electric circuit is high (using the well-known V = R I rule). When the diaphragm is popped out by the vibrating air, it causes the carbon granules (right behind it) to separate out. In this case, those carbon granules are acting like a high-resistance resistor in the electrical circuit. Hence, the current flowing though the circ