Telecommunications interview questions

A well-known telecommunications company uses this pop quiz for oral and written examinations of applicants for engineering positions.

1. A 2MB PCM(pulse code modulation) has…

a) 32 channels
b) 30 voice channels & 1 signaling channel.
c) 31 voice channels & 1 signaling channel.
d) 32 channels out of which 30 voice channels, 1 signaling channel, & 1 synchronization channel.

Ans: c

2. Time taken for 1 satellite hop in voice communication is…

a) 1/2 second
b) 1 seconds
c) 4 seconds
d) 2 seconds

Ans: (a)

3. Max number of satellite hops allowed in voice communication is:

a) only one
b) more han one
c) two hops
d) four hops

Ans: (c)

4. What is the maximal decimal number that can be accommodated in a byte?

a) 128
b) 256
c) 255
d) 512

Ans: (c)

5. Conditional results after execution of an instruction in a micro processor is stored in…

a) register
b) accumulator
c) flag register
d) flag register part of PSW(Program Status Word)

Ans: (d)

6. Frequency at which VOICE is sampled is…

a) 4 KHz
b) 8 KHz
c) 16 KHz
d) 64 KHz

Ans: (a)

7. Line of sight is…

a) Straight Line
b) Parabolic
c) Tx & Rx should be visible to each other
d) none of the above

Ans: (c)

8. Purpose of PC(Program Counter) in a MicroProcessor is…

a) To store address of TOS(Top Of Stack)
b) To store address of next instruction to be executed.
c) count the number of instructions.
d) to store base address of the stack.

Ans: (b)

9. What action is taken when the processor under execution is interrupted by a non-maskable interrupt?

a) Processor serves the interrupt request after completing the execution of the current instruction.
b) Processor serves the interrupt request after completing the current task.
c) Processor serves the interrupt request immediately.
d) Processor serving the interrupt request depends upon the priority of the current task under execution.

Ans: (a)

10. The status of the Kernel is…

a) task
b) process
c) not defined.
d) none of the above.

Ans: (b)

11. What is the nominal voltage required in subscriber loop connected to local exchange?

a) +48 volts
b) -48 volts
c) 230 volts
d) 110 volts

12. To send a data packet using datagram , connection will be established…

a) before data transmission.
b) connection is not established before data transmission.
c) no connection is required.
d) none of the above.

Ans: (c)

13. Word alignment is…

a) aligning the address to the next word boundary of the machine.
b) aligning to an even boundary.
c) aligning to a word boundary.
d) none of the above.

Ans: (a)

14. When a C function call is made, the order in which parameters passed to the function are pushed into the stack is…

a) left to right
b) right to left
c) bigger variables are moved first than the smaller variales.
d) smaller variables are moved first than the bigger ones.
e) none of the above.

Ans: (b)

15. What is the type of signaling used between two exchanges?

a) inband
b) common channel signaling
c) any of the above
d) none of the above.

Ans: (a)

16. Buffering is…

a) the process of temporarily storing the data to allow for small variation in device speeds
b) a method to reduce cross talks
c) storage of data within transmitting medium until the receiver is ready to receive.
d) a method to reduce routing overhead.

Ans: (a)

17. Memory allocation of variables declared in a program is…

a) allocated in RAM.
b) allocated in ROM.
c) allocated on stack.
d) assigned to registers.

Ans: (c)

18. A software that allows a personal computer to pretend as a computer terminal is …

a) terminal adapter
b) bulletin board
c) modem
d) terminal emulation

Ans: (d)

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10 Comments on Telecommunications interview questions

  1. Posted 4/14/2004 at 2:49 am | Permalink

    Q17. How do you differentiatate between option a and c. Stack is on RAM!

  2. BJT
    Posted 5/30/2004 at 9:48 pm | Permalink

    Q1 is actually asking what are the channels on a (ISDN) T1 line, bear inmind that America uses T1, whereas Europe uses E1 and they are different. A 2MB PCM could be a windows .wav file for as far as the question offers.

  3. BJT
    Posted 5/30/2004 at 9:54 pm | Permalink

    Q6 is actually (b) 8kHz, however the highest frequency sampled is 4kHz.
    Remember 8kHz * 8 Bits = 64Kbits/sec.
    hmm… who wrote the answers?

  4. Wireless_Mouse
    Posted 4/27/2005 at 11:16 am | Permalink

    Q11 is (a). And for an extension phone, the answer should be +24V.

  5. sandeep kumar chaturvedi
    Posted 10/21/2005 at 8:53 am | Permalink

    Answer for qu.1 is actually 32 channels out of which 30 are voice channels, half of the rest(2)is signalling, and the same is for synchronisation
    therefore the correct answer is (d)

  6. The OSea
    Posted 9/15/2006 at 12:14 pm | Permalink

    Q(6) Highest frequency for a human voice around 4KHz. Based on the Nyquist Theorem, sampling is done at 2*Freq(high), twice the highest freq which should be 8Khz, but in industry its 2.2*Freq(high)

  7. pravin
    Posted 11/7/2006 at 12:56 am | Permalink

    11. What is the nominal voltage required in subscriber loop connected to local exchange?

    a) +48 volts
    b) -48 volts
    c) 230 volts
    d) 110 volts

    for the above Q. ans is not given
    the ans is

  8. ankit vyas
    Posted 5/28/2007 at 8:47 pm | Permalink

    question 11
    ans not given
    ans is -48 volts

  9. Arief
    Posted 9/22/2007 at 1:02 am | Permalink

    The answer of Q1 is incorret. Correct Answer is d. This is true for T1 or E1.

  10. Arief
    Posted 9/22/2007 at 1:19 am | Permalink

    I mean there is 1 signaling channel & 1 synchronization channel for either T1 or E1

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