Term
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Definition
| Plain Old Telephone System / Service |
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Term
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Definition
| Pulse Code Modulation - most common method of encoding an analog voice signal into digital |
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Term
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Definition
You need to sample at twice the highest frequency to achieve good quality.
4000 Hz X 2 = 8000 samples per second.
8000 X 8bits = 64000 bps, or 64Kbps
64Kbps is the "magic number" for ISDN lines |
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Term
| a-law to u-law conversion is the responsibility of which country? |
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Definition
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Term
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Definition
| Connects home telephone to Central Office switch (CO) |
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Term
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Definition
| Central Office Switch, also known as Class 5, or End Office Switch |
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Term
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Definition
| "Tandem Switches" interconnect through trunks to End office switches (CO) |
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Term
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Definition
User-to-network -> end user to PSTN
Network-to-network -> switch to switch |
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Term
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Definition
| Public Switched Telephone Network |
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Term
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Definition
| Dual Tone Multi-Frequency - Most common User-to-Network signalling method. In-band |
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Term
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Definition
| Integrated Services Digital Network - User-to-Network Signalling, uses out-of-band signalling. |
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Term
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Definition
| Multi-Frequency - Network to Network (switch to switch) In-band signalling method. |
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Term
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Definition
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Term
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Definition
| Signalling System 7 - Network to Network (switch to switch), out of band signalling method. Allows PSTN to offer Custom Local Area Signalling Services (CLASS) |
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Term
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Definition
11 digits - 3 parts
NPA - Numbering Plan Area (area code)
NXX - Central Office Code (exchange)
XXXX - Station Number |
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Term
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Definition
| Real-Time Transport Protocol - currently the cornerstone for carrying real-time traffic accross IP networks. Runs atop UDP. One way delay of no more than 150 ms |
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Term
| VoIP Call-Control Protocols |
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Definition
| SIP, H.323, MGCP, and H.248/MEGACO |
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Term
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Definition
| Analog Terminal Adapters - allow analog equipment to connect to VoIP systems. |
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Term
Network to Network > SONET
Fiber media |
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Definition
Synchronous Optical NETwork
OC-3 - 155.52Mbps
OC-12 - 622.08Mbps
OC-48 - 2.488Gbps |
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Term
Network to Network > T1/E1
Twisted pair |
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Definition
T1 - 1.544 Mbps
E1 - 2.048 Mbps |
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Term
Network to Network > T3/E3
Coaxial Cable |
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Definition
T3 - 28 T1s (672 x 64 kbps) 44.736 Mbps
E3 - 16 E1s (512 64 kbps) 34.368 Mbps |
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Term
Network to Network > T4
microwave link? |
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Definition
| 168 T1s (4032 x 64 kbps) 274.176 Mbps |
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Term
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Definition
| Inter eXchange Carrier - long distance network carrier |
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