11. Eight stations are competing for the use of the shared channel using the modified Adaptive free walk protocol by Gallager. If the stations 7 and 8 are suddenly become ready at once, how many bit slots are needed to resolve the contention?
A. 1 slots
B. 5 slots
C. 10 slots
D. 14 slots
12. When two computers communicate with each other, they send information back and forth. If they are separated by a reasonable distance, they can send and receive the information through a direct cable connection which is called a null-modem connection. Presently what is the maximum distance in metres permitted in this null-modem connection?
A. 80
B. 100
C. 30
D. 150
E. None of the above
13. Modulation in which the two binary values are represented by two different amplitudes of the carrier frequency is known as
A. Amplitude-shift keying
B. Amplitude
C. Amplitude modulation
D. Aloha
E. None of the above
14. You have been contracted to install a windows NT network in an office that is located in a strip mall. The office is located next to the power plant of the building, so a UPS (uninterruptible power supply) has already been installed. What type of cable should you use for the network cabling? Choose the best answer.
A. TI
B. UTP
C. Fiber-optic
D. PSTN
E. STP
15. Communication circuits that transmit data in both directions but not at the same time are operating in
A. a simplex mode
B. a half-duplex mode
C. a full-duplex mode
D. an asynchronous mode
E. None of the above