1
Q
Analog and Digital Signals
A
Analog - Analog is a method of transmitting information by a continuous but varying signal. (ex. like a dimmer light switch. Many possible positions in a dimmer light switch)
An analog waveform is a smooth flowing line alternating from a high level to a low level. A sine wave.
Digital - Digital is a method of storing or transmitting information by discrete, non-continuous impulses. (ex. like a standard light switch, on or off. 1 means on 0 means off)
A digital wave form is a series of squares with high and low voltage states.
2
Q
Sampling Rate
A
How many times, per second, a digital sample is taken of the analog signal. (ex. A sample rate of 44.1 kHz is 44,100 samples taken every second. This technique is called Pulse Code Modulation PCM)
How many times, per second, a digital sample is taken of the analog signal. (ex. A sample rate of 44.1 kHz is 44,100 samples taken every second. This technique is called Pulse Code Modulation PCM)
3
Q
Nyquist-Shannon Sampling Theorem
A
- An analog signal can be reconstructed if it is encoded using a sampling rate that is greater than twice the highest frequency sampled. (ex. Human hearing extends to 20kHz so the sampling rate for digital audio should be greater than 40 kHz)
4
Q
Bit Depth
A
The number of bits used to describe a sampled voltage level. Also knows as quantization because it involves assigning a quantity to the signal being measured. Greater bit depth gives a more accurate representation of the sampled signal. As the number of bits increases, the number of possible states increases exponentially. A bit depth of 16 will have 65,536 possible states. 2 to the 16th power.
5
Q
Bit Rate
A
The measurement of the quantity of information over time in a digital signal stream. The higher the bit rate, the better the signal quality. Quantified in bits per second or bps.
6
Q
Compression
A
- A process that reduces very large files to smaller, manageable sizes. Compressed files discard unnecessary information, which reduces the size of digital files and makes them easier to transmit and store. This process is used extensively in computer applications, such as streaming audio or visual content over the Internet.
7
Q
***Two Elements of a digital file
A
(Container and CODEC
8
Q
CODEC (Coder/Decoder
A
An electronic device that converts analog signals, such as video and audio signals, into digital form and compresses them to conserve bandwidth on a transmission path. Uses an algorithm, or a set of procedures, to encode and decode file information.
9
Q
Container -
A
The structure of a file where the data is stored. It defines how the data is arranged to increase performance and which codecs are used.
10
Q
Lossless Compression
A
- A process that retains the original quality of a file after it has been compressed and decompressed. (ex. WinZip)
11
Q
Lossy Compression
A
- A Lossy Compression form of compression that gives an approximation of the original data by eliminating redundant or unnecessary information.
12
Q
Noise -
A
Any electrical signal present in a circuit other than the desired signal.
13
Q
Network for Data and AV
***All networks have two main parts
A
nodes and connections.***
14
Q
Node
A
Node - Any active device that sends and receives network data. (ex. Computer, mobile device, video server, projector)
15
Q
Connections -
A
Connections - The physical means by which data travels from one node to another. (ex. RF, copper cabling, light). A passive device like a patch panel also falls into this category.
16
Q
***Every device that connects to the network must have what
A
a network interface card (NIC) and associated MAC address.***
17
Q
Network Interface Card (NIC)
A
- An interface that allows you to connect a device to a network.
18
Q
MAC Address
A
The Actual hardware address, or number, of your NIC device. Uses a globally unique 48-bit number expressed as 6 groups of two hexadecimal numbers, separated by a hyphen or colon. The first part of the number indicates the manufacturer and the second part of the number is a serial number for the product or circuit component. Each NIC has its own associated MAC address.
19
Q
Network Switch
A
Network Switch - Provides a physical connection between multiple devices. As each device connects the switch collects and stores its MAC address. Allows connected devices to the same switch to communicate directly with each other via Ethernet, using only MAC addresses to locate each other.
20
Q
Unmanaged switches have no
A
no configuration options. Plug in a device and it connects.
21
Q
Manages switches
A
- Allow the adjustment of port speeds, set up virtual local area networks (VLANs), configure quality of service, monitor traffic.
22
Q
Router
A
- Forwards data between devices that are not directly physically connected. Marks the border between a local area network and a wide area network. When traffic leaves a local area network (travels beyond the switch) routers direct it until it reaches its final destination. When data reaches the router it examines the packet’s logical address (IP address) to determine the next destination
23
Q
Gateway
A
- A router that connects a private network to outside networks. All data that travels to the internet must pass through a gateway. Routers below the gateway will forward packets destined for any device that can’t be found on the private network to the gateway. When traffic arrives from outside the private network, the gateway forwards it to the appropriate router below. Also translates data from one protocol to another. (ex. When data leaves a private network to travel across the Internet, a gateway translates it from a baseband to a broadband protocol.)
24
Q
Server
A
- A piece of computer hardware or a program that runs on a computer alongside other programs that does nothing but provide services to dependent nodes
25
Thin Server
- A server that offers only one service.
26
The most common physical transmission methods
Over copper as voltage, over glass as visible light, and over air as radio frequencies.
27
The most popular transmission medium for local area networks (LANs
is copper. Copper network cables are almost exclusively twisted pair.
28
Category - Ethernet standards under the EIA/TIA 568 standard. Most common are Cat 5, Cat 5e, and Cat 6.
Category Cable
Category - Ethernet standards under the EIA/TIA 568 standard. Most common are Cat 5, Cat 5e, and Cat 6.
Category Cable
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Cat 1 -
Telephone and doorbell type connections (unrecognized by TIA/EIA
30
Cat 2
- 4 Mbps (unrecognized)
31
Cat 3
up to 16 MHz - typically 10 Mbps (Defined in TIA/EIA-568-B)
32
Cat 4
Cat 4 - up to 20 MHz - typically 16 Mbps (unrecognized)
33
Cat 5
Cat 5 - up to 100 MHz - typically 100 Mbps (unrecognized)
34
cat 5 e
Cat 5e - up to 100 MHz - typically both 100 Mbps and 1 Gbps (Defined)
35
Cat 6
- up to 250 MHz - typically both 100 Mbps and 1 Gbps (Defined
36
Cat 6a -
Cat 6a - up to 500 MHz - typically 10 Gbps (Defined)
37
Cat 7 -
Cat 7 - up to 600 MHz - typically 10 Gbps (Informal ISO/IEC 11801 Class F cabling)
38
Cat 7a -
Cat 7a - up to 1000 MHz - suitable for 40 Gbps (Informal ISO/IEC 11801 amendment 1 Class F cabling)
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CAT 5e - The designation for 100-ohm unshielded twisted-pair cables. Associated with connecting hardware specified for data transmission up to 100 Mbps. Adds specifications for far end crosstalk to the obsolete Cat 5 standard.
CAT 5e - The designation for 100-ohm unshielded twisted-pair cables. Associated with connecting hardware specified for data transmission up to 100 Mbps. Adds specifications for far end crosstalk to the obsolete Cat 5 standard.
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CAT 6 - Conductors have more twists per inch. Also operate at a high speed (measured in gigabits), meaning high frequencies with tiny wavelengths. This means Cat 6 cables are susceptible to noise so they should be shielded for delivery of AV signals like HDBaseT.
CAT 6 - Conductors have more twists per inch. Also operate at a high speed (measured in gigabits), meaning high frequencies with tiny wavelengths. This means Cat 6 cables are susceptible to noise so they should be shielded for delivery of AV signals like HDBaseT.
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CAT 6a - Augments form of Cat6 capable of 10 Gbps data transmission. Very high frequency transmissions have to account for alien crosstalk (AXT), noise of unknown origin that can't be cancelled out by active equipment like typical near and far-end crosstalk. Cat 6a are designed to compensate for AXT but even so UTP Cat 6a shouldn't be used for cable runs of more than 55m and should be bundled loosely to limit crosstalk. STP Cat 6a cable has better protection against EMI and RFI, and can therefore be used on longer cable runs.
CAT 6a - Augments form of Cat6 capable of 10 Gbps data transmission. Very high frequency transmissions have to account for alien crosstalk (AXT), noise of unknown origin that can't be cancelled out by active equipment like typical near and far-end crosstalk. Cat 6a are designed to compensate for AXT but even so UTP Cat 6a shouldn't be used for cable runs of more than 55m and should be bundled loosely to limit crosstalk. STP Cat 6a cable has better protection against EMI and RFI, and can therefore be used on longer cable runs.
42
RJ-45 -
- The connector used for Cat cabling. For many Ethernet connections, only four of the eight wires in the cables are actually used for data transmission. Gigabit Ethernet for faster, as well as certain special devices, use the other four conductors for other purposes. The specific pin-out depends on the connection standard you are using.
43
There are two wiring formats within the IEEE 802 standard
: T568-A and T568-B. Both formats are acceptable to use; As the IT manager which format is used within the facility. The T568A termination standard uses the green wires for transmit and the orange wires for receive. T568B uses the orange for transmit and green for receive.
44
```
T568A
Pin 1 -
Pin 2 -
Pin 3 -
Pin 4 -
Pin 5 -
Pin 6 -
Pin 7 -
Pin 8 -
```
```
T568A
Pin 1 - Green/White
Pin 2 - Green
Pin 3 - Orange/White
Pin 4 - Blue
Pin 5 - Blue/White
Pin 6 - Orange
Pin 7 - Brown/White
Pin 8 - Brown
```
45
```
T568B
Pin 1 -
Pin 2 -
Pin 3 -
Pin 4
Pin 5 -
Pin 6 -
Pin 7 -
Pin 8 -
```
```
T568B
Pin 1 - Orange/White
Pin 2 - Orange
Pin 3 - Green/White
Pin 4 - Blue
Pin 5 - Blue/White
Pin 6 - Green
Pin 7 - Brown/White
Pin 8 - Brown
```
46
If a cable is terminated with T568-A on one end and T568-B on the other, the cable is known as a
a crossover cable. A crossover cable allows two devices, such as two computers, to connect and share information without the use of a switch or router that normally does the crossover electronically.
In a crossover cable, all pairs have opposite pinning on the near and far end. Crossover cables are not used as network infrastructure cables in TCP/IP networks. They may be used to connect a network device console port to a computer so configuration changes can be made.
47
Fiber is a glass medium used for
for transmitting modulated light, from point A to point B. The make-up of fiber is: Core (glass medium used to carry light), Cladding (surrounds core and reflects light back moving signal down the fiber), and Coating (protects fiber from damage)
48
Fiber optic cable offers
high bandwidth and maintains total electrical isolation. Allows fiber to maintain signal integrity in noisy environments, experiencing little signal degradation over long distances. Totally immune to electromagnetic and radio frequency interference. Also popular for security reasons, it doesn't burn, and withstands aging and corrosion. More difficult to covertly capture data from fiber optic than copper or radio waves because you have to physically intercept the path of light.
49
There are two modes, or paths of light, behind fiber optic
Single-mode and multimode
50
Single-mode is
Single-mode is a straight shot, the light path is small in diameter which makes the signal path mostly straight, with some of the signals bouncing off of the walls of the glass.
Single-mode is a straight shot, the light path is small in diameter which makes the signal path mostly straight, with some of the signals bouncing off of the walls of the glass.
51
Multimode
Multimode some of the signal goes straight down the fiber while the rest of the signal bounces off of the cladding. Because the signals are not shooting straight down the cable like in single-mode the signals will take longer to reach the end of the fiber and some of the light will disperse as it travels. As a result, network data can typically travel farther over single-mode than multimode.
52
The most popular connectors for fiber optic cables are:
: the ST, LC, and SC connectors.
ST connector - Can be found on transmitter-receiver equipment and is very similar to the BNC. It's a bayonet connector, meaning that all you have to do is "stab and twist" to lock it into place. This keeps the fiber and ferrule from rotating during connection. This connector can be used on both multimode and single-mode fiber.
LC connector - Much smaller in diameter than the ST and is used for basic wiring applications. It has great low loss qualities and is knows as a "push, pull" connector.
SC connector - Is larger in diameter than the LC. It is a "stab and click" connector, which means that when the connector is pushed in or pulled out, there is an audible click due to the attachment lock. Great connector to get in and out of tight spaces.
53
Wi-Fi - A wireless connection defined by the IEEE 802.11 standard. The speed of the Wi-Fi connection depends on the RF signal strength and the revision of 802.11 with which you connect. As signal strength weakens the speed of the connection slows. The number of users accessing the wireless devices also affects connect speed. A, G, and N are the most commonly used versions of Wi-Fi in the field today.
802. 11a - 5 GHz - Typically 27 Mbps, Max 72 Mbps
802. 11b - 2.4 GHz - Typically 5 Mbps, Max 11 Mbps
802. 11g - 2.4 GHz - Typically 22 Mbps, Max 54 Mbps
802. 11n - 5 GHz or 2.4 GHz - Typically 144 Mbps, Max 600 Mbps
802. 11ac - 5 GHz - Typically 866Mpbs - 2.5 Gbps, Max 6.7 Gbps (theoretical)
Wi-Fi - A wireless connection defined by the IEEE 802.11 standard. The speed of the Wi-Fi connection depends on the RF signal strength and the revision of 802.11 with which you connect. As signal strength weakens the speed of the connection slows. The number of users accessing the wireless devices also affects connect speed. A, G, and N are the most commonly used versions of Wi-Fi in the field today.
802. 11a - 5 GHz - Typically 27 Mbps, Max 72 Mbps
802. 11b - 2.4 GHz - Typically 5 Mbps, Max 11 Mbps
802. 11g - 2.4 GHz - Typically 22 Mbps, Max 54 Mbps
802. 11n - 5 GHz or 2.4 GHz - Typically 144 Mbps, Max 600 Mbps
802. 11ac - 5 GHz - Typically 866Mpbs - 2.5 Gbps, Max 6.7 Gbps (theoretical)
54
WiFi Advantages
It's convenient. Wireless hotspots are everywhere.
Encourages mobility and productivity. Workers can conduct business from anywhere.
Require little infrastructure. Access points are "plug and play"
They're scalable. If you need more client nodes you just have to add more access points.
They're cheap. All you need is an access point.
55
WiFi Disadvantages
Limited range. Restrictions on the range of Wi-Fi devices are established by the 802.11 equipment standards and the United States Federal Communication Commission (FCC).
Susceptible to radio frequency interference (RFI).
Equipment selection and placement can be tricky. Proper placement, antenna selection, and signal strength are key. Building contruction materials impact RF propagation. Some construction materials will dampen RF signals. Others act as reflectors, enhancing signal quality.
They can get expensive. Low cost at first but you may need to purchase additional repeaters or highly directional antennas to expand the network's range. Cost of building an extended wireless network can grow quickly.
They're slow. Wi-Fi- bandwidth is capped at 150 Mbps. If you need to stream live high-definition video, Wi-Fi is not a dependable option.
They're insecure. Wi-Fi networks are far more susceptible to malicious attacks than wired networks, because it's so easy for devices to connect. For this reason they are severely restricted or completely prohibited in certain business, financial, and Government/Military facilities.
56
Local Area Networks (LAN)
Networks are classified according to whether nodes use physical or logical addresses to communicate.
Local Area Networks use physical addresses to communicate. The physical address is the Media Access Control (MAC) address. It is hard coded into each node and it never changes.
MAC address are unique - no other device on the planet should have the same MAC address as your video server or laptop.
LANS are usually privately owned and operated. They have fast and hhigh capacity.
Most real-time AV network protocols are designed for LAN speeds/capacity. Includes AVB, Ethersound, and CobraNet.
57
LANs require devices to be
be directly, physically connected. This limits geographical size, you can only send an electrical signal so far before it degrades beyond use.
Data travels across a LAN addressed to the MAC address of one of the devices on the LAN. A switch receives the packet and examines the MAC address to which is is addressed. The switch forwards the packet to the appropriate device.
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One of the most important characteristics of any given network is its topology.
. Network topology is a determining factor in how far data must travel in order to reach its destination. Topology also bears on which network connections carry the most traffic. Both factors are crucial in determining whether and how to send AV signals over a network. Two basic categories: physical topologies and logical topologies.
Physical topology is the "way we wired it" or how it is physically connected together.
Logical topology is the electrical routing and control of data. Maps the flow of data within a network: which network segments and devices must data pass through in order to get from its source to its destination. Not defined or constrained by phycial topology.
Topology reveals how many devices data has to pass through before it gets to its destination. Many real-time AV protocols have a limited number of hops, usually les than 10.
Topology shows which devices and connections have to handle the most data. Helps network engineers figure out which parts of their network need the most capacity.
Topology shows where a network's weak spots are. When you look at a local area network topology, you should always look for single points of failure
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A single point of failure is any device whose failure will cause the entire system to fail. No more than 20 devices should be affected by any one single point of failure.
A single point of failure is any device whose failure will cause the entire system to fail. No more than 20 devices should be affected by any one single point of failure.
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Devices can be connected on a local area network in several different ways:
Star topology - all nodes connect to a central point, like a router, switch, or hub. Star networks are hierarchical. Each node has access ot the other nodes on the central point through the central point. If any one node fails, information still flows. The central device is a single point of failure. If it fails, communication stops.
Extended Star topology - Star topologies are often extended to include more than one layer of hierarchy. If any device fails, access to the devices below it are cut off, but the rest of the network continues to work. The central device remains a single point of failure, if it fails communication stops.
Meshed topology - each node connects to every other node. Meshed topologies provide fast communication and excellent redundancy, ensuring that the failure of no one device can bring down the whole network. Providing physical connections between every device is really expensive though. Fully meshed networks are rare.
Partially meshed topology - each node connects to several other nodes, but not all. Partially meshed topologies provide good redundancy, ensuring that several devices must fail at the same time before communications cease.
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Ethernet - The standard for how data is sent across Local Area Networks from one physically connected device to another. This is the standard for LANs.
IEEE 802.3 Ethernet Standards - Defines a data frame format, network design requirements, and physical transport requirements for Ethernet networks.
When IP data is sent across a LAN, it is encapsulated inside an Ethernet Frame. The Ethernet frame is generated by the device's Network Interface Card (NIC). The frame has a header and footer that surround the packet, arriving at the destination intact.
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types of either net
Types of Ethernet:
10Mbps Ethernet
Ethernet Type Physical Medium Max Distance between Nodes
10Base-T Cat 3 or higher copper twisted pair 328 feet (100m)
10Base-FL 62.5/125 micrometer multimode optical fiber-850 nm wavelength 6,560 feet (2000m)
100Mbps Ethernet aka Fast Ethernet
Ethernet Type Physical Medium Max Distance between Nodes
100Base-T4 Cat 3 twisted pair cable, using all four pairs 328 feet (100m)
100Base-T2 Cat 3 twisted pair cable, using two pairs 328 feet (100m)
100Base-TX Cat 5 twisted pair cable or better, using two pairs 328 feet (100m)
100Base-FX 62.5/125 micrometer multimode optical fiber-1300nm wavelength 6,560 feet (2000m) for full-duplex; 13,52 ft (412m) for half-duplex
100Base-SX 62.5/125 micrometer multimode opticalfiber - 850 nm wavelength 1,804 feet (550m)
Gigabit Ethernet
Ethernet Type Physical Medium Max Distance between Nodes
1000Base-T Cat 5 twisted pair cable or better, using four pairs 328 feet (100m)
1000Base-TX Cat 6 twisted pair, using two pairs 328 feet (100m)
1000Base-CX Four-conductor balanced shielded twisted pair 82 feet (25m)
1000Base-SX Two options: 62.5/125 micrometer mulimode optical fiber or 50/125 micrometer multimode optical fiber Depends of fiber type: 62.5/125 micrometer up to 902 feet (275m) or 50/125 micrometer up to 1804 feet (550m)
1000Base-LX Three options: 62.5/125 micrometer multimode optical fiber, 50/125 micrometer multimode optical fibers, or Single mode optical fiber. 1300 nm wavelength Depends on fiber type: 62.5/125 micrometer is 1804 feet (550m), 50/125 micrometer is 1804 feet (550m), and Single mode is 3.1 miles (5km)
1000Base-LX10 Single mode optical fiber - 1300 nm wavelength 6.2 miles (10 km)
10 Gigabit Ethernet
Ethernet Type Physical Medium Max Distance between Nodes
10GBaseT Cat 5e twisted pair cable or better 328 feet (100 m) for shielded; 180 feet (55 m) for unshielded
10GBaseCX4 Four-conductor balanced shielded twisted pair 49 feet (15 m)
10GBaseS 50/125 micrometer multimode optical fiber - 800 nm wavelength 213 feet (65 m)
10GBaseLX4 Two options: 62.5/125 multimode obtical fiber or 9 micrometer single mode optical fibers Depends on fiber type: 62.5/125 micrometer is 984 feet (300 m) and Single mode is 6.2 miles (10km)
10GBaseLR 9 micrometer single mode optical fiber - 1310 nm wavelength 6.2 miles (10km)
10GBaseER 9 micromode single mode optical fiber - 1550 nm wavelength 24.8 miles (40km)
40/100 Gigabit Ethernet
Ethernet Type Physical Medium Max Distance between Nodes
40GBase-CR4 Four-conductor balanced shielded twisted pair 32 feet (10 m)
40GBase-SR4 Two options: OM3 multimode optical fiber or OM4 multimode optical fiber Depends on fiber type: OM3 - 328 feet (100 m) or OM4 - 125 feet (410 m)
40GBase-LR4 Single mode optical fiber 6.2 miles (10 km)
100GBase-CR10 Four-conductor balanced shielded twisted pair 32 feet (10 m)
100GBase-SR10 Two options: OM3 multimode optical fiber or OM4 multimode optical fiber Depends on fiber type: OM3 - 328 feet (100 m) or OM4 - 125 feet (410 m)
100GBase-LR4 Single mode optical fiber 6.2 miles (10 km)
100GBase-ER4 Single mode optical fiber 24.8 miles (40 km)
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Wide Area Networks (WANs)
A wide area network is a network that connects one or more LANs together. WANs use logical addresses to communicate. The logical address is an Internet Protocol (IP) address.
The nodes on a WAN are routers. If a LAN is connected to outside networks via a WAN a router sits at the top of its network hierarchy. Any data that needs to travel to a device outside the LAN gets forwarded to the router. The router strips the packet of identifying LAN information, like the MAC address of the originating device, before forwarding the packet to its intended IP address. This protects the devices on the LAN. A WAN can be any size. It can connect two LANs within the same building. It may span the entire globe, like the world's largest WAN, the internet. Unlike LAN connections, long-distance WAN connections are rarely privately owned. Usually, WAN connections are leased from the Internet Service Providers (ISPs). WAN communications travel farther than LAN communications. As a result, they're slower but usually only by a fraction of a second. As a result, many networked AV protocols can't travel over WANs.
WAN topologies can be placed into a few common categories
