UGC NET CSE | June 2012 | Part 2 | Question: 16

Question

In which circuit switching, delivery of data is delayed because data must be stored and retrieved from RAM?

• A. Space division
• B. Time division
• C. Virtual
• D. Packet

Answer 1

Answer : Time Division

Time-division multiplexing (TDM) is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fraction of time in an alternating pattern.

Reference : TDM

Comments

can u explain options a,c,d iam not able to get them

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1. Space division
2. virtual
3. packet   what do these mean

Answer 2

Circuit switching today uses either of two technologies

1. Space Division

2. Time Division

In Space Division, the path in the circuit are separated from one another spatially. This technology was originally desiged for use in Analog networks but is currently used in both Analog and Digital Networks.

2. Time division multiplexing (TDM) is a communications process that transmits two or more streaming digital signals over a common channel. In TDM, incoming signals are divided into equal fixed-length time slots. After multiplexing, these signals are transmitted over a shared medium and reassembled into their original format after de-multiplexing. Time slot selection is directly proportional to overall system efficiency.

Time division multiplexing (TDM) is also known as a digital circuit switched.

The advantage of TDM is that it needs no cross-points. Its disadvantage is the TSI(Time Slot Interchange)-is that processing each connection create delays. Each time slot must be stored by RAM, then retrieved and passed on.

other two options are not appropriate according to question so simply discard them.

Answer 3

Circuit Switching is two types one is Space Divisons and 2nd is Time Divisons.

In Time Division, There are two methodologies are used 1st is TSI(TIME SLOT INTERCHANGE) and 2nd is TDM Bus.

TSI changes the ordering of time slots based on desired connection and it has RAM to store DATA and flip the time slot.

In TDM Bus, there are several input and output connected to high speed bus.only one at particular instant of time.

So, Answer is B

for more detailing see http://nptel.ac.in/courses/106105080/pdf/M4L1.pdf