36. Videotex is a combination of

A. television
B. communication
C. computer technology
D. All of the above
E. None of the above

37. Which of the following frequency ranges is used for AM radio transmission?

A. Very Low Frequency : 3 kHz to 30 kHz
B. Medium Frequency : 300 kHz to 3 MHz
C. High Frequency : 3 MHz to 30 MHz
D. Very High Frequency : 30 MHz to 300 MHz
E. None of the above

38. Baseband is

A. transmission of signals without modulation
B. a signal all of whose energy is contained within a finite frequency range
C. the simultaneous transmission of data to a number of stations
D. All of the above
E. None of the above

39. A 4 KHz noise less channel with one sample ever 125 per sec is used to transmit digital signals. Differential PCM with 4 bit relative signal value is used. Then how many bits per second are actually sent?

A.32 Kbps
B.64 Kbps
C.8 Kbps
D.128 Kbps.

40. X.21 is

A. a method of determining which device has access to the transmission medium at any time
B. a method access control technique for multiple-access transmission media
C. a very common bit-oriented data link protocol issued by ISO
D. network access standard for connecting stations to a circuit-switched network
E. None of the above