0 letters and 10 numerals to meet railway requirements. It was while the United States Congress in 1837 was considering a petition to authorize a New York to New Orleans Chappe semaphore line that Samuel F. B. Morse argued for the U.S. government to support his electrical telegraph. The government appropriated the money in early 1843. The first operational line was between New York and Baltimore. Within 20 years the telegraph covered the United States from coast to coast. The first phase of electrical communications was completed. It revolutionized our lives (Ref. 1). 2.3 BASIC CONCEPTS OF ELECTRICITY FOR COMMUNICATIONS 2.3.1 Early Sources of Electrical Current Rather crude dry cell batteries were employed in the earlier periods of telegraph as an electrical current source. Their development coincided with the Morse telegraph 2.3 BASIC CONCEPTS OF ELECTRICITY FOR COMMUNICATIONS Figure 2.1a Graphic notation of a single dry cell. Figure 2.1b Graphic notation of a "battery" of dry cells. 1.5 V 1.5) V Figure 2.1c How dry cells can be connected in series to increase voltage. (ca. 1835-1840). They produced about 1.5 volts (direct current) per cell. To achieve a higher voltage, cells were placed in series. Figure 2.1a shows the standard graphic notation for a cell; Figure 2.1b shows the graphic symbol for a battery made up of several cells. A drawing of a battery made up of four cells is illustrated in Figure 2.1c. A dry cell stores chemical energy from which, when its positive electrode is connected through some resistive device to the negative electrode, a current will flow. A battery of cells was the simple power source for a telegraph circuit. 2.3.2 The Electrical Telegraph: An Early Form of Long-Distance Communications Let's connect a battery terminal (or electrode) with a length of copper wire looping it back to the other electrode. A buzzer or other sound-generating device is inserted into that loop at the farthest end of the wire before looping back; we now have the essentials of a telegraph circuit. This concep