CH 1 Tradition vs Unified Voice QUESTIONS Flashcards
System designed for large businesses with thousands or tens of thousands of users. Usually permits direct dialing to a particular office phone.
PBX
An adapter card installed in a PBX to connect to another PBX or the PSTN.
Trunk card
An adapter card installed in a PBX to connect to telephone handsets.
Line card
Central Office
CO
Public Switched Telephone Network
PSTN
The location where telephone equipment, such as telephone switches, are located.
CO
Private Branch Exchange
PBX
The telephony systems that together span the USA and connect residential users, business users, and business telephony systems.
PSTN
System designed for a business of about 50 users or fewer. Often does not allow for direct dialing to a particular office.
Key System
The most common device on the PSTN. Converts audio into electrical signals.
Analog telephone
Signaling the beginning of a call by connecting the tip (positive) and ring (negative) wires to form an electrical circuit.
Loop Start Signaling
A connection between the customer premises (home or business) and the telecommunications service provider.
Local Loop
when a call on a ling is being placed simultaneously with a call being received and thus neither can be completed.
Glare
Signaling the beginning of a call by the PBX sending a ground signal over the wires.
Ground Start Signaling
A connection between two switches or a switch and a business system that carries multiple conversations of the same set of wires.
Trunk
Has the highest MOS of common codecs.
G.711
Has the highest MOS of commonly used compression codecs.
G.729
Uses 8 kbps
G.729
Uncompressed audio
G.711
Supported by all VOIP devices.
G.711
Uses 32 kbps
G.726
Uses 16 kbps
G.728
Uses 64 kbps for transmission
G.711
In this type of signaling, the 24th time slot on a T1 line is used for signaling and the 17th time slot is used on an E1 line for signaling.
Common Channel Signaling (CCS)
Is an out-of-band signaling method.
Common Channel Signaling (CCS)
An example of this signaling is SS7, a switch-to-switch protocol.
Q.931
Is an in-band signaling method.
Channel associated signaling (CAS)
The signaling protocol used by ISDN (not the type of protocol).
Common Channel Signaling (CCS)
Also called robbed-bit signaling.
Channel associated signaling (CAS)
Sending multiple signals (calls) over a single set of wires by giving each signal its own time slot.
time-division multiplexing
An example of this signaling is ISDN.
Common Channel Signaling (CCS)Q.931
Signaling information is transmitted in the same bandwidth as the voice.
Channel associated signaling (CAS)
Signaling is transmitted in a separated, dedicated signaling channel.
Common Channel Signaling (CCS)
Taking a periodic measurement of an analog signal.
Sampling
Finding patterns in digital information and representing them in a way that reduces the bandwidth needed to transmit the signal.
Compression
A G.711 codec format used in the USA and Japan.
u-law
Converting a waveform into a discrete, numeric, digital form.
Quantization
A G.711 codec format used in Europe and elsewhere.
a-law
Which of the following are true about the Mean Opinion Score (MOS)? (Select ALL that apply.)
a. The value is in the range 0 to 255.
b. The value is in the range 1 to 5.
c. It is an objective measure of quality.
d. It is a subjective measure of quality.
b. The value is in the range 1 to 5.
d. It is a subjective measure of quality.
The Nyquist theorem states that __.
a. Adequate voice quality can be realized by taking samples at twice the highest audio frequency used.
b. CD quality voice can be realized by taking samples at twice the highest audio frequency used.
c. Adequate voice quality can be realized by digitizing voice into one byte of data.
d. Adequate voice quality can be realized by taking samples at twice the highest audio amplitude used.
a. Adequate voice quality can be realized by taking samples at twice the highest audio frequency used.
Uses even-numbered ports and UDP packets.
Real-time Transport Protocol (RTP)
Chips added to an ISR to enable the router to perform voice-related tasks.
Digital Signaling Processor (DSP)
A bundle of chips on one card to put into an ISR to handle voice communications.
Packet Voice DSP modules (PVDM)
Uses odd-numbers ports and UDP packets.
Real-time Transport Control Protocol (RTCP)
The higher the number on this card, the more voice communications it can handle.
Packet Voice DSP modules (PVDM)
The protocol that carries statistics about the performance of the audio and video delivery.
Real-time Transport Control Protocol (RTCP)
The protocol that carries the multimedia information (audio or video usually) as its payload.
Real-time Transport Protocol (RTP)
Name and explain the components of the ITU E.164 standard.
E.164 is a standard addressing scheme for telephones, to organize and identify them used the same way as we use IP addresses in the data network. If I am telephone A and I want to contact telephone B - I, telephone A would enter 10 digits belonging to telephone B. Same as PC A would send a packet to PC B by inputing PC B’s IP address.
Three components: 1. Country code 2. National code 3. Subscriber number
