# Nyquist Theorem and other Telecom Questions

Please see the attached file.

Is the Nyquist theorem true for optical fiber or only for copper wire?

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.

What is the percent overhead on a T1 carrier; that is what percent of the 1.544 Mbps are not delivered to the end user?

What is the difference between message switching network and packet switching?

Sometimes when a mobile user crosses the boundary from one cell to another the current call is abruptly terminated even though all transmitters and receivers are functioning perfectly Why?

A CDMA receiver gets the following chips: (+1 +1 +1 +1 +3 -1 -1 +3). Assuming the chip sequences for four stations as defined below, which stations transmitted, and which bit did each one send?

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Is the Nyquist theorem true for optical fiber or only for copper wire?

The Nyquist theorem is a property of mathematics and has nothing to do with technology. It says that if you have a function whose Fourier spectrum does not contain any sines or cosines above f, then by sampling the function at a frequency of 2f you capture all the information there is. Thus, the Nyquist theorem is true for all media.

(Ref: http://www.teunisott.com/CIS451.F.03/Solutions/HomeWork4.htm)

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.

22,000

(Ref: http://books.google.com/books?id=Pd-z64SJRBAC&pg=PP1&lpg=PP1&sig=ACfU3U0ge-Q0DgLfOTz_PQoWXlprMgiSkQ&q=end+office#PPA120,M1) Paragraph 2.

What is the percent overhead on a T1 carrier; that is what percent of the 1.544 Mbps are not delivered to the end user?

In figure 2-33 the T1 carrier have 24 Channel, each channel ...

#### Solution Summary

6 Telecom related questions including Nyquist theorem, T1 overhead and CDMA coding.