Which statement is false about modems?
a. modems are usually used in pairs (2 at a time)
b. a receiving modem demodulates and a sending modem modulates
c. most modems support several modem standards so that they can communicate with a variety of modems
d. modems may operate at a lower speed that that for which they are rated, especially if they detect noise in the communication line
e. modems must always be internal to the computer
Answer: modems must always be internal to the computer
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Telecom Chapter 3
- _________ is one way that data rates over traditional telephone lines can be increased dramatically.
- Digital Subscriber Line:
- Inverse multiplexing means:
- Statistical time division multiplexers differ from time division multiplexers because they:
- Which of the following types of multiplexing is least efficient for data transmission?
- _____ separate channels to reduce interference between channels in frequency division multiplexing.
- Frequency division multiplexing:
- The type of multiplexer that divides the circuit horizontally into different light frequencies that are transmitted simultaneously across many channels is
- A(n) ___________ divides one high-speed communication circuit into several lower speed circuits for the primary reason of saving communication line costs.
- A 56K modem that uses the V.90 standard:
- When converting analog voice data to digital signals, Pulse Code Modulation samples the incoming voice signal _______ times per second.
- __________ refers to the difference between the original analog data and the approximation of that data using the techniques for translating from analog data to digital signals.
- Codec refers to:
- When V.34 modems initially connect, they must go through a ____________ sequence to test the circuit and determine the optimum combination of symbol rate and modulation technique that will produce the highest throughput.
- _____ is a modem standard that uses Lempel-Ziv encoding to compress data.
- The acronym, Modem, stands for _________________.
- Using TCM that sends 6 bits per each signal and a voice grade line with a bandwidth of 3000 Hz (assume: no noise on the line), the data capacity would be ___________ bits per second.
- Which of the following statements is true?
- To get more "bandwidth" in a digital transmission, you must:
- ________ is the approximate bandwidth of traditional telephone circuits.
- The typical range of human hearing is:
- The _____________ of a circuit determines a circuit's capacity.
- ______ is a unit of signaling speed that indicates how often the signal changes on a communication circuit.
- TCM stands for: