DIGITAL T-CARRIERS AND MULTIPLEXING

Question 1

The transmission of information (of any form) from one or more source to one or more destination over the same transmission medium

Answer 1

Multiplexing

Question 2

What are the different Domains to accomplish Multiplexing?

Answer 2

Space Division Multiplexing, Time Division Multiplexing, Frequency Division Multiplexing, Wavelength Division Multiplexing

Question 3

Domain of multiplexing where transmission from multiple sources occur on the same facility but NOT at the same time.

Answer 3

Time Division Multiplexing

Question 4

Unsophisticated form or multiplexing that simply constitutes propagating signals from different sources on different cables that are contained on the same trench (transmission medium).

Answer 4

Space Division Multiplexing

Question 5

Most prevalent encoding technique used for TDM (Time Division Multiplexing) digital signals.

Answer 5

Pulse Code Modulation (PCM)

Question 6

Line speed of DS-0 (Digital Signal Level 0) channels?

Answer 6

64kbps

Question 7

What is the Input Signal range and Sampling Rate of DS-0 channels?

Answer 7

Input Signal Range: 0-4kHz, Sampling Rate: 8kHz

Question 8

How many bits per sample is in a TDM (Time Division Multiplexing) Frame?

Answer 8

8 bits per sample

Question 9

Time it takes to transmit one TDM (Time Division Multiplexing) Frame. Equal to the time interval when sampling, therefore it is the reciprocal of the Sampling Rate.

Answer 9

Frame Time, 1/8000 seconds, 125 microseconds

Question 10

In TDM (Time Division Multiplexing) the datastream is divided into _____ aka _____.

Answer 10

Time Slot, Epoch

Question 11

In TDM (Time Division Multiplexing) what is the general formula for a channel’s data transmission rate?

Answer 11

Sampling Rate (Samples per Second) x TDM Frame (Bits per Sample)

Question 12

in TDM (Time Division Multiplexing) what is the general formula for the line speed?

Answer 12

Number of Channels x Data Transmission Rate per Channel

Question 13

Formula for Bit Rate?

Answer 13

Number of Channels x Input Bit Rate

Question 14

Formula for Frame Rate?

Answer 14

Input Bit Rate (Convert to Bits) x Time Slot Bits

Question 15

A communication system that uses digital pulses rather than analog signals to encode information.

Answer 15

Digital Carrier System

Question 16

How many Voice Band Channels can a T1-Digital Carrier System TDM multiplex?

Answer 16

24 Voice Bands Channels

Question 17

Bandwidth or Frequency range of Voice Bands or Audio Signals?

Answer 17

300Hz - 3kHz

Question 18

Within a T1-Carrier System, _____ performs sampling, encoding and multiplexing of 24 voice band channels.

Answer 18

Channel Banks

Question 19

Line Speed of T1-Digital Carrier System Time Division Multiplexing with the synchronization bit?

Answer 19

1.544Mbps
24 channels, 8bps/channel
192 bits per frame, +1 (sb)
193 bits per frame x 8000 samples per second

Question 20

What does the “D-type” in D-type Channel Banks stands for?

Answer 20

Digital or Data Transmission

Question 21

What type of encoding technique does D-type Channel Banks use?

Answer 21

Sign-Magnitude Code

Question 22

How many frames in a superframe?

Answer 22

12 Frames

Question 23

How many time slots per frame in a T1 Carrier System?

Answer 23

24 time slots for 24 channels

Question 24

How many time slots per frame in a E1 Carrier System?

Answer 24

30 time slots for 30 channels

Question 25

How many bits are encoded per time slots?

Answer 25

8 bits

Question 26

A communication format where the frames are grouped together to increase synchronization, error detection and control.

Answer 26

Superframe TDM (Time Division Multiplexing) Format

Question 27

In Superframe TDM (Time Division Multiplexing) Format, what are substituted in frames 6 and 12?

Answer 27

Signaling Bits

Question 28

A _____ bit is substituted to frames 6 and 12 of Superframe TDM (Time Division Multiplexing) Format, what is substituted in frame 6? What is frame 6 called?

Answer 28

Signaling, Most Significant Bit (MSB), A-channel Signaling Bit

Question 29

A _____ bit is substituted to frames 6 and 12 of Superframe TDM (Time Division Multiplexing) Format, what is substituted in frame 12? What is frame 12 called?

Answer 29

Signaling, Least Significant Bit (LSB), B-channel Signaling Bit

Question 30

In Superframe TDM (Time Division Multiplexing) Format, what do you call frames 1-6?

Answer 30

A-highway

Question 31

In Superframe TDM (Time Division Multiplexing) Format, what do you call frames 7-12?

Answer 31

B-highway

Question 32

How many bits per frame?

Answer 32

193 bits

Question 33

What do you call the extra bit per frame? Where is it placed?

Answer 33

Frame bit, at the beginning of the frame

Question 34

How many frames in an Extended Superframe Format?

Answer 34

24 Frames

Question 35

How many frames in the Extended Superframe Format is used as Synchronization Bit? What are the frame numbers?

Answer 35

6 Frames, Frame No: 4, 8, 12, 16, 20, 24

Question 36

How many frames are used for Error Detection Code? What are the frame numbers?

Answer 36

6 Frames, Frame No: 1, 5, 9, 13, 17, 21

Question 37

What do you call the Error Detection Code?

Answer 37

CRC-6 (Cyclic Redundancy Checking)

Question 38

In Extended Superframe Format, how many bits is reserved for Management Channel?

Answer 38

12 bits

Question 39

In Extended Superframe Format, what do you call the Management Channel?

Answer 39

Facilities Data Link (FDL)

Question 40

What are the frame numbers used for Management Channel?

Answer 40

2, 3, 6, 7, 10, 11, 14, 15, 18, 19, 22, 23

Question 41

The Extended Superframe Format supports a four-bit signaling word, where is it placed when encoded, and what frames?

Answer 41

Placed on second Least Significant Bit and on every 6th frame (6, 12, 18, 24).

Question 42

Type of Communication Service that allows consumers to share a T-Carrier Line.

Answer 42

Fractional T-Carrier Service

Question 43

In a T1/2 Carrier Service, How many channels are available and what is the line speed?

Answer 43

12 channels, 1.544Mbps/2 = 0.772Mbps

Question 44

Central location where digital signals are routed to perform routine maintenance and troubleshooting.

Answer 44

Digital Cross-Connect (PPT) or Digital Signal Cross-Connect (Historical naming Convention) or DSX

Question 45

Device that allows audio and video communications between users.

Answer 45

Picturephone Terminal

Question 46

Device used to send, receive and process digital data.

Answer 46

Data Terminal