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24 Cards in this Set
- Front
- Back
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- The first voice transmission was send by whom and in what year?
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- It was sent by Alexander Graham Bell in 1876
Chapter 1 |
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- What is Line noise?
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- It is the introduction of static into a voice network
Chapter 1 |
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- Analog communication is a mixture of what?
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- Analog communication is a mix of time and amplitude
Chapter 1 |
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- What is accumulated noise?
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- It is the process of going through several amplifiers with one voice signal.
Chapter 1 |
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- What is the problem with amplifier with respect to signal?
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- An amplifier does not clean the signal as it amplifies, but simply amplifies the distorted signal.
Chapter 1 |
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- What is it that in digital networks, line noise is less of an issue?
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- It’s because repeaters not only amplify the signal, but clean it to its original condition. Therefore, when the signals are repeated, a clean sound is maintained.
Chapter 1 |
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- What is the Nyquist theorem?
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- If you sample at twice the highest frequency on a voice line, you achieve good-quality voice transmission
Chapter 1 |
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- PCM is on the most common method to perform what?
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- Is the most common method of encoding an analog voice signal into a digital stream of 1s and 0s.
Chapter 1 |
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- What are the two basic variations of 64 Kbps PCM that are commonly used?
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- U-law (commonly used in North America)
and the a-law ( the standard in Europe) Chapter 1 |
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- What is a trunk?
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- It is the communication path between several central office switches.
Chapter 1 |
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- What are the two types of PSTN signaling methods that runs over various transmission media?
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- User- to-network signaling
[This is how the end user communicates with the PSTN] - Network-to-network signaling [This is how the switches in the PSTN intercommunicate.] Chapter 1 |
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- What is the most common signaling method for user-to-network analog communication?
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- DTMF (Dual Tone Multi- Frequency)
- Also known as in band- signaling because the tones are carried through the voice path. - When you pick up the phone and press the digits, the tone passes from your phone to the central office switch to which you are connected and tell the switch what number you want to call. Chapter 1 |
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- ISDN uses another method of signaling known as what?
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- Out-of-Band signaling
- With this method, the signaling is transported on a channel separate from the voice. Chapter 1 |
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- Name 4 benefits that out of band signaling offers;
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- Signaling is multiplexed
- Glare is reduced - A lower post dialing delay - Higher bandwidth Chapter 1 |
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- Name 2 in-band signaling types used in network-to-network communications
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- MF [it’s similar to DTMF except that MF signals from switch to switch]
- RBS [ ] Chapter 1 |
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- Name and define an out-of-band signaling method used in network-to-network signaling
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- SS7 or C7 in European countries
[SS7 is a method of sending messages between switches for basic call control and for CLASS – Custom Local Area Signaling Services] Chapter 1 |
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- Name 3 benefits of moving to an SS7 network
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- Reduced post-dialing delay
- Increased call completion - Connection to the IN [Intelligent Network- The public switched telephone network architecture of the 1990s.] Chapter 1 |
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- What are the 2 numbering plan used with the PSTN?
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- 1. NANP [North American Numbering Plan]
- 11 digits dialing plan that contains 3 parts; - The numbering Plan Area (or area code) - Central Office Code - Station Number - - 2. ITU [International Telecommunication Union Telecommunications Standardization Sector] - Recommendation of E.164 specifies that the following information must be used to route a call to a specific subscriber. - Country Code - National Destination Code - Subscriber Number Chapter 1 |
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- List 4 drawbacks of the PSTN which explains why many business drivers are striving to change to a new network.
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- 1.Data has overtaken voice as the primary traffic on many network built for voice
- 2.The PSTN cannot create and deploy features quickly enough - 3.Data/Voice/Video cannot on the PSTN as currently built - 4.The architecture built for voice is not flexible enough to carry data. Chapter 1 |
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- List the 7 original RBOC’s (or LEC)
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- Pacific Telesis
- Southwestern Bell - Nynex - Bell Atlantic - Southern Bell - US West - NYNEX Chapter 1 |
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- What is RTP?
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- Real time transport protocol, used in addition to a user datagram protocol (UDP)/IP header to provide time stamping.
- An Internet protocol for transmitting real-time data such as audio and video Chapter 1 |
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- What is the job of the call control protocols?
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- Their functions is the tell the RTP streams where the terminate and where to begin. Call control accomplishes this task by translating between IP addresses and phone numbering plans [Ex: H,323, SGCP, MGCP and SIP
Chapter 1 |
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- What is Jitter?
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- The difference between when a packet is supposed to be received and when it is actually received
Chapter 1 |
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- What is SIP?
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- Application-layer control (signaling) protocol for creating, modifying and terminating sessions with one or more participants.
Chapter 1 |
