Cvoice 3 - Understanding Ip Telephony Applications

Front 1

- Name 3 analog interfaces;

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Back 1

- Foreign exchange stations (FXS)
- Foreign exchange office (FXO)
- Ear & Mouth (E&M)

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Front 2

- Explain how the Foreign Exchange Station (port) is used;

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Back 2

- It’s used to provide a direct connection to an analog telephone, a fax machine or a similar device
- The FXS contains the coder-decoder (codec)

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Front 3

- What is a codec (coder-decoder)?

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Back 3

- It converts the spoken analog voice wave into a digital format for processing by the voice-enabled device.

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Front 4

- Explain how the Foreign Exchange Office (port) is used;

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Back 4

- Allows an analog connection to be directed at the CO of a PSTN or to a station interface on a PBX.
- The FXO provides either pulse or DTMF digits for outbound dialling.

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Front 5

- What is an FX trunk?

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Back 5

- In PSTN terminology, an FXO-to-FXS connection is also referred to as a foreign exchange trunk.
- The FX is CO trunk that has access to a distant CO (act as a long-distance extension of a local telephone line.)

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Front 6

- Explain how the E&M interface is used;

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Back 6

- It provides signalling for analog trunking
- Analog trunk circuits connect automated system (PBXs) and networks (COs)

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Front 7

- Name 3 basic digital voice interfaces;

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Back 7

- T1; 24 channels
- E1; 32 channels
- BRI; Used to connect PBX voice into the network (Two 64 Kbps B channels and a 16 kbps D channel for Q.931 signalling)

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Front 8

- A T1 carries either CAS or CCS, explain how they are configured;

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Back 8

- When T1 uses CAS is by Robbed-Bit Signaling
- When T1 uses CCS, Q.931 signalling is used on a single channel, typically the last channel.

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Front 9

- Name the 3 physical connections options for IP phones;

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Back 9

- Single cable (one cable connects the telephone and the PC to the switch)
- Multiple cables (one for the PC and the other one for the telephone)
- Multiples switches (Telephone and PC connects to separate switches)

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Front 10

- Name 4 factors that must be addressed in the logical configuration for connecting IP phones.

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Back 10

- IP addressing
- VLAN assignment
- Spanning tree
- Classification and queuing

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Front 11

- Data traffic that is supporting phone on the VLAN can reduce the quality of VOIP traffic, how can you resolve this?

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Back 11

- By isolating the traffic on a separate VLAN for each of the ports connected to a telephone. (note;that the IP phone has the capability to prioritize voice frames)

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Front 12

- In the Enterprise environment, exist 2 types of call processing solutions, what are they?

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Back 12

- Centralized call processing; enterprise- wide access for call and voice services are controlled from a central site.(all the components of the voice system are controlled by a single centralized call agent, such as CallManager regardless of their physical location.)
- Distributed call processing; the components of a voice network at each location can act independently

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Front 13

- What’s a Unity server?

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Back 13

- Central repository for unified messaging, such as voice mail, e-mail and fax

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Front 14

- Explain how calls are processed in a Campus LAN environment?

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Back 14

- Example: All desktop phones connect to Ethernet switches and are controlled by CallManager applications.

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Front 15

- What is the function of the SRTS component of a centralized voice enterprise network?

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Back 15

- Provides local call-processing capabilities in case of a WAN outage.

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