26. Bulletin board system

A. is a public access message system
B. is a modem capable of accepting commands
C. converts analog signals to digital signals
D. converts digital signals to analog signals
E. None of the above

27. In OSI model, which of the following layer provides error-free delivery of data?

A. Data link
B. Network
C. transport
D. Session
E. None of the above

28. Error detection at the data link level is achieved by?

A. Bit stuffing
B. Hamming codes
C. Cyclic Redundancy codes
D. Equalization
E. None of the above

29. The area of coverage of a satellite radio beam is known as

A. Footprint
B. Circular polarization
C. Beam width
D. Identity
E. None of the above

30. Which of the following data transmission media has the largest terrestrial range without the use of repeaters or other devices?

A. Hardwiring
B. Microwave
C. Satellite
D. Laser
E. None of the above