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block 11 3a + 3b > block 6 1A telephony fundamentals > Flashcards

block 6 1A telephony fundamentals Flashcards

1
Q

What are the voltages the PSTN phone switch utilize and what are they used for?

A

-48v DC: On-hook (ready to receive a call)

90v AC: Ring voltage

4-6v DC: Off-hook (customer wants to make a call or it is answering a ‘ring’ on the phone

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2
Q

What is the Integrated Service Digital Network? (ISDN)

A
  • communication standards for simultaneous digital transmission of voice, video, data over traditional public switched telephone network
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3
Q

Explain the differences between the BRI and the PRI.

A

BRI (Basic Rate Interface)
- two 64 B-channels ,one 16 Dchannel.
- circuit can dedicate 128 Kbps toward voice/data transmission on a single copper cable pair.
- used for STE + VTC connections.
- B-Channels deliver data, D-channels used for signal management.

Primary Rate Interface (PRI)
- PRI = 23 64 B-channels one 64 D channel( totaling 24 channels. )
- PRI user can have up to 1, 544 Kbps.
- PRIs are primarily used for trunks between switches.

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4
Q

What happens to the analog signal when it is sampled and how does it turn digital when encoded with binary code using pulse code modulation?

A
  • analog signal converted to digital signal.
  • original signal transmitted by digital means.
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5
Q

Describe bandwidth.

A

maximum data that can be transmitted over a network connection in a given amount of time

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6
Q

How does sampling work in the Nyquist Principal, and when a higher rate is sampled, it can produce what?

A
  • Sampling frequency greater x2 maximum frequency of signal being sampled
  • produce perfect reconstruction of original signal
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7
Q

How are VTC audio and video signals compressed and decompressed?

A

in Realtime using a CODEC

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8
Q

Sound travels short distances but with the help of what device, it can travel further.

A

The telephone

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9
Q

What can affect the design of a telephone?

A

The frequency and amplitudes required

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10
Q

What controls the entire basic telephony network?

A

Call processing server/call manager.

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11
Q

Describe backbone cabling.

A

Backbone cabling = inter/intra-building cable connections in structured cabling between entrance facilities, equipment rooms and telecommunications closets

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12
Q

What are the mediums in which sound can travel?

A

Solid, liquid, and gas

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13
Q

What are the differences between land lines and dedicated lines?

A
  • Land lines =connect many different locations
  • Dedicated lines = connect 2 places continually (24 hours)
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14
Q

Define frequency.

A
  • number of sound waves that pass a fixed point in a unit of time. (hertz hz)
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15
Q

Explain the differences between the PBX and the DID

A

A private branch exchange (PBX) is
- a small-scale telephone switch/software used to route calls for a building or organization.

Direct Inward Dialing (DID) is a service that provides a block of telephone numbers for calling into a company’s PBX system. (gets you directly to who you want to reach without going through an automated system.)

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16
Q

What is E911 used for?

A

Wireless E911 (Enhanced 911)

  • displays telephone number + physical location of caller on operator’s screen.
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17
Q

Describe what PSAPS is and what the VOIP network being adopted.

A

Public Safety Answering Points (PSAPs) across the country need to be upgraded to digital/Internet Protocol (IP)-based 911 system.

-Next Generation 911 (NG911 is VOIP).(provides texts,video,etc slow implementation)

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18
Q

What is Class of Service?

A
  • Each telephone line assigned Class of Service (CoS)
    or
  • Calling Search Space (CSS) controls types of calls made from that line.
19
Q

What is MLPP and describe its functions.

A

Multi-level Precedence and Preemption (MLPP)
- service allows authorized users to place priority calls, and if necessary, to preempt lower-priority calls.

20
Q

Translate each section of a 10-digit U.S. phone number.

A

Three-digit numbering plan area (NPA) code

Three-digit Exchange code (NXX); the ‘exchange’ is the central office to which that number is assigned.

Four digits for the directory number (DN); assigned to the individual user.

21
Q

Explain the differences between Customer Group and Device Pool.

A
  • Customer Group = PSTN systems
  • Device Pool= (VoIP) systems.
22
Q

What are the benefits of the Caller ID service?

A

displays a caller’s phone number,location, and associated billing or subscriber name are shown.
The CID feature is particularly useful when screening known, unknown, or unwanted calls.

23
Q

Explain both circuits switching and the automatic exchange switch.

A

Circuit Switching: connect telephone calls. used for the Public Switched Telephone Network (PSTN).

Automatic exchange switch: purpose eliminate human switchboard operator to complete the call.
The automatic switch used a series of selector based electrical switches in order to complete the circuit.

24
Q

What does the call processing server do?

A
  • center of VoIP phone system
  • terminating all VoIP control connections.
25
Q

What is packet switching?

A

chopping data into small packets, with address telling the network devices where to send them.

26
Q

Define the DSN and how it functions in a crisis.

A

(Defense Switch Network)
The DSN assures connection availability w/ Multi-Level Precedence and Preemption (MLPP).

an emergency happens, phone line is needed, your call will be cut off so someone with higher priority can use the line.

27
Q

_____ is a methodology and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks.

A

VOIP (Voice over internet Porotocol)

28
Q

All VoIP calls are dependent on what two qualities of the IP network?

A

Quality and Reliability

29
Q

Describe the 5 major VoIP components

A

VoIP Protocols: A protocol= set of rules that defines how communications devices should communicate with each other and transmit data.

IP Network: provides infrastructure, backbone, necessary for a VoIP implementation.

Call Processing Server - stores end device IDs, directory numbers, configuration settings, and establishes calls. Program Installed on a Computer.

Endpoint devices - IP phones, soft phones, applications, computers, printers.

Voice Gateways: provide connectivity between VoIP components and PSTN components.

30
Q

What does a codec do?

A
  • device or computer program that encodes/decodes digital data stream
  • signal or compresses and decompresses medial files.
31
Q

Name and define each VoIP signaling protocol.

A

Signaling Protocols: used for VoIP components communicate w/ each other to prepare for the actual call.

Transport Protocols: After VoIP call is established, IP phones exchange voice packets with each other directly.

Proprietary: owned by specific entity

Non-Proprietary: free range (universal)

32
Q

Name and define the VoIP transport protocol.

A
  • needed for IP phones to exchange voice packets w/ each other.

-responsible for data formatting, identifying codec, sampling, carry actual voice traffic.

33
Q

What is the difference between proprietary and non-proprietary?

A

Non-proprietary - anyone can use it.

Proprietrary - Only the company who owns it can use it.

34
Q

Which of the named VOIP protocols are proprietary? Which are non-proprietary?

A

Proprietary :
- Skinny Client Control Protocol (SCCP or Skinny): SCCP is a Cisco proprietary VoIP signaling protocol.

non-proprietary :

  • H.323, framwork defines components, functions, protocols to send voice/video over IP network
  • Session Initiation protocol (SIP), establish/terminate mulitmedia sessions (layer 4) Voip signaling protocol most often used
  • Real-Time Transport Protocol (RTP) responsible for managing the transmission of the voice data once call is established. Primary standard for transmitting audio over IP network.
35
Q

In what scenario, would you utilize a voice gateway?

A

to access the IP network.

36
Q

PSTN is analog phone whereas VoIP is __________ phone.

A

IP phone (TCP/IP phone or digital signaling).

37
Q

QoS is implemented on which layer 3 network device?

A

Routers provide QOS.

38
Q

Define QoS. What factors does QoS use to prioritize traffic?

A
  • ability to give priority to certain types of network traffic.
  • based on the application, user, or service that generated the traffic.
39
Q

What does the router do for a packet?

A

forward packets from one subnet to another

40
Q

What is the network switch used for?

A
  • provide physical connectivity for devices to access an IP network.

provide two key services -
- Power Over Ethernet (POE)
- Voice Virtual Local Area Network (VLAN)

41
Q

Define DSCP and what it uses in the header.

A

Differentiated Services Code Point (DSCP) - classifying/managing network traffic + providing (QoS) in layer 3 IP networks.
- uses 6-bit differentiated Service (DS) field in IP header for packet classification.

42
Q

How can you group IP phone?

A

Subnet

43
Q

What is the difference between VoSIP and SVoIP?

A

In a SVoIP implementation = connected to unsecure network. makes IP phone responsible for encrypting voice traffic.

Voice over Secure Internet Protocol (VoSIP)
- In a VoSIP implementation, connected to secure IP network.

block 11 3a + 3b (10 decks)

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