21. Sending a file from your personal computer’s primary memory or disk to another computer is called
A. uploading
B. downloading
C. logging on
D. hang on
22. Business meeting and conferences can be held by linking distantly located people through a computer network. Not only the participants exchange information but are able to see each other. What is it called?
A. Telemeeting
B. Telemailing
C. Teleconferencing
D. Teletalking
E. None of the above
23. What frequency range is used for microwave communications, satellite and radar?
A. Low Frequency : 30 kHz to 300 kHz
B. Medium Frequency : 300 kHz to 3 MHz
C. Super High Frequency : 3000 MHz to 30000 MHz
D. Extremely High Frequency :30,000 MHz
E. None of the above
24. Which of the following statements is incorrect?
A. The difference between synchronous and asynchronous transmission is the clocking derived from the data in synchronous transmission
B. Half-duplex line is a communication line in which data can move in two directions, but not at the same time.
C. Teleprocessing combines telecommunications and DP techniques in online activities.
D. Batch processing is the preferred processing mode for telecommunication operations
E. None of the above
25. If the ASCII character H is sent and the character I is received, what type of error is this?
A. single-bit
B. multiple-bit
C. burst
D. recoverable