How many end office codes were there pre-1984, when each end office was named by its three-digit area code and the first three digits of the local number? Area codes started with a digit in the range 2–9, had a 0 or 1 as the second digit, and ended with any digit. The first two digits of a local number were always in the range 2–9. The third digit could be any digit.
Answer to relevant QuestionsUsing only the data given in the text, what is the maximum number of telephones that the existing U.S. system can support without changing the numbering plan or adding additional equipment? Could this number of telephones ...A modem constellation diagram similar to Fig. 2-25 has data points at the following coordinates: (1, 1), (1, -1), (-1, 1), and (-1, -1). How many bps can a modem with these parameters achieve at 1200 baud?Why has the PCM sampling time been set at 125 µsec?In Fig. 2-37, the user data rate for OC-3 is stated to be 148.608 Mbps. Show how this number can be derived from the SONET OC-3 parameters.Make a rough estimate of the number of PCS micro cells 100 m in diameter it would take to cover San Francisco (120 square km).
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