Black Box Explains... Why go wireless?
• Its great for communicating in harsh climates or in areas where its expensive to run cable. Wireless solutions are well suited for use in military applications, farming, refineries, mining,... more/see it nowconstruction, and field research.
• Because sometimes you just cant run wire, like in historic buildings or hazmat areas.
• When its physically or legally impossible to support conventional hard-wired RS-232 communications, wireless networking may be your only answer.
• It gives you quick, temporary connections at trade shows, and fast reconfigurations—even troubleshooting or remote field testing.
• It provides reliable disaster relief when all else fails! Count on wireless networks to maintain mission-critical links when disaster strikes.
• Its more affordable, more reliable, and faster than ever before.
• Best of all, no FCC licensing required! collapse
Black Box Explains...How to maximize your wireless range.
Product Data Sheets (pdf)...Palm-Sized Ethernet Switches,
There are four simple rules that enable you to transmit wireless communications up to their maximum range:
• Try to keep a direct line between the transmitter and receiver.
• Minimize... more/see it nowthe number of walls and ceilings between the transmitter and receiver. Such obstructions reduce the range.
• If there are obstructions, be sure the wireless signal passes through drywall or open doorways and not other materials.
• Keep the transmitter and receiver at least 3 to 6 feet (0.9 to 1.8 m) away from electrical devices or appliances, especially those that generate extreme RF noise. collapse
Black Box Explains...MIMO wireless.
Product Data Sheets (pdf)...Pure Networking PCI Bus Network Adapters
Multiple-Input/Multiple-Output (MIMO) is a part of the new IEEE 802.11n wireless standard. It’s a technique that uses multiple signals to increase the speed, reliability, and coverage of wireless networks. It... more/see it nowtransmits multiple datastreams simultaneously, increasing wireless capacity to up to 100 or even 250 Mbps.
This wireless transmission method takes advantage of a radio transmission characteristic called multipath, which means that radio waves bouncing off surfaces such as walls and ceilings will arrive at the antenna at fractionally different times. This characteristic has long been considered to be a nuisance that impairs wireless transmission, but MIMO technology actually exploits it to enhance wireless performance.
MIMO sends a high-speed data stream across multiple antennas by breaking it into several lower-speed streams and sending them simultaneously. Each signal travels multiple routes for redundancy.
To pick up these multipath signals, MIMO uses multiple antennas and compares signals many times a second to select the best one. A MIMO receiver makes sense of these signals by using a mathematical algorithm to reconstruct the signals. Because it has multiple signals to choose from, MIMO achieves higher speeds at greater ranges than conventional wireless hardware does.
Black Box Explains...Gigabit Ethernet.
As workstations and servers migrated from ordinary 10-Mbps Ethernet to 100-Mbps speeds, it became clear that even greater speeds were needed. Gigabit Ethernet was developed for an even faster Ethernet... more/see it nowstandard to handle the network traffic generated on the server and backbone level by Fast Ethernet. Gigabit Ethernet delivers an incredible 1000 Mbps (or 1 Gbps), 100 times faster than 10BASE-T. At that speed, Gigabit Ethernet can handle even the traffic generated by campus network backbones. Plus it provides a smooth upgrade path from 10-Mbps Ethernet and 100-Mbps Fast Ethernet at a reasonable cost.
Gigabit Ethernet is a true Ethernet standard. Because it uses the same frame formats and flow control as earlier Ethernet versions, networks readily recognize it, and its compatible with older Ethernet standards. Other high-speed technologies (ATM, for instance) present compatibility problems such as different frame formats or different hardware requirements.
The primary difference between Gigabit Ethernet and earlier implementations of Ethernet is that Gigabit Ethernet almost always runs in full-duplex mode, rather than the half-duplex mode commonly found in 10- and 100-Mbps Ethernet.
One significant feature of Gigabit Ethernet is the improvement to the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) function. In half-duplex mode, all Ethernet speeds use the CSMA/CD access method to resolve contention for shared media. For Gigabit Ethernet, CSMA/CD has been enhanced to maintain the 200-meter (656.1-ft.) collision diameter.
Affordability and adaptability
You can incorporate Gigabit Ethernet into any standard Ethernet network at a reasonable cost without having to invest in additional training, cabling, management tools, or end stations. Because Gigabit Ethernet blends so well with your other Ethernet applications, you have the flexibility to give each Ethernet segment exactly as much speed as it needsand if your needs change, Ethernet is easily adaptable to new network requirements.
Gigabit Ethernet is the ideal high-speed technology to use between 10-/100-Mbps Ethernet switches or for connection to high-speed servers with the assurance of total compatibility with your Ethernet network.
When Gigabit Ethernet first appeared, fiber was crucial to running Gigabit Ethernet effectively. Since then, the IEEE802.3ab standard for Gigabit over Category 5 cable has been approved, enabling short stretches of Gigabit speed over existing copper cable. Today, you have many choices when implementing Gigabit Ethernet:
1000BASE-X refers collectively to the IEEE802.3z standards: 1000BASE-SX, 1000BASE-LX, and 1000BASE-CX.
The S in 1000BASE-SX stands for short. It uses short wavelength lasers, operating in the 770- to 860-nanometer range, to transmit data over multimode fiber. Its less expensive than 1000BASE-LX, but has a much shorter range of 220 meters over typical 62.5-µm multimode cable.
The L stands for long. It uses long wavelength lasers operating in the wavelength range of 1270 to 1355 nanometers to transmit data over single-mode fiber optic cable. 1000BASE-LX supports up to 550 meters over multimode fiber or up to 10 kilometers over single-mode fiber.
The C stands for copper. It operates over special twinax cable at distances of up to 25 meters. This standard never really caught on.
Gigabit over CAT5—1000BASE-TX
The 802.3ab specification, or 1000BASE-TX, enables you to run IEEE-compliant Gigabit Ethernet over copper twisted-pair cable at distances of up to 100 meters of CAT5 or higher cable.
Gigabit Ethernet uses all four twisted pairs within the cable, unlike 10BASE-T and 100BASE-TX, which only use two of the four pairs. It works by transmitting 250 Mbps over each of the four pairs in 4-pair cable. collapse
Pure Networking II Gigabit Ethernet Switch User manual
User Manual for the LGB105A and LGB108A (Version 1)
Pure Networking II 10/100 Ethernet Switch User Manual
User Manual for LB016A (version 1)
USB-Powered 10/100 Switch User Manual
User Manual for the LBS005A & LBS008A (Version 2)
Black Box Explains...Wireless Ethernet standards.
The precursor to 802.11b, IEEE 802.11 was introduced in 1997. It was a beginning, but 802.11 only supported speeds up to 2 Mbps. And it supported two entirely different... more/see it nowmethods of encodingFrequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread Spectrum (DSSS). This led to confusion and incompatibility between different vendors equipment.
802.11b is comfortably established as the most popular wireless standard. With the IEEE 802.11b Ethernet standard, wireless is fast, easy, and affordable. Wireless devices from all vendors work together seamlessly. 802.11b is a perfect example of a technology that has become both sophisticated and standardized enough to really make life simpler for its users.
The 802.11b extension of the original 802.11 standard boosts wireless throughput from 2 Mbps all the way up to 11 Mbps. 802.11b can transmit up to 200 feet under good conditions, although this distance may be reduced considerably by the presence of obstacles such as walls.
This standard uses DSSS. With DSSS, each bit transmitted is encoded and the encoded bits are sent in parallel across an entire range of frequencies. The code used in a transmission is known only to the sending and receiving stations. By transmitting identical signals across the entire range of frequencies, DSSS helps to reduce interference and makes it possible to recover lost data without retransmission.
The 802.11a wireless Ethernet standard is new on the scene. It uses a different band than 802.11b—the 5.8-GHz band called U-NII (Unlicensed National Information Infrastructure) in the United States. Because the U-NII band has a higher frequency and a larger bandwidth allotment than the 2.4-GHz band, the 802.11a standard achieves speeds of up to 54 Mbps. However, its more limited in range than 802.11b. It uses an orthogonal frequency-division multiplexing (OFDM) encoding scheme rather than FHSS or DSSS.
802.11g is an extension of 802.11b and operates in the same 2.4-GHz band as 802.11b. It brings data rates up to 54 Mbps using OFDM technology.
Because it's actually an extension of 802.11b, 802.11g is backward-compatible with 802.11b—an 802.11b device can interface directly with an 802.11g access point. However, because 802.11g also runs on the same three channels as 802.11b, it can crowd already busy frequencies.
Super G® is a subset of 802.11g and is a proprietary extension of the 802.11g standard that doubles throughput to 108 Mbps. Super G is not an IEEE approved standard. If you use it, you should use devices from one vendor to ensure compatibility. Super G is generally backwards compatible with 802.11g.
80211n improves upon 802.11g significantly with an increase in the data rate to 600 Mbps. Channels operate at 40 MHz doubling the channel width from 20 MHz. 802.11n operates on both the 2.4 GHz and the 5 GHz bands. 802.11n also added multiple-input multiple-output antennas (MIMO) collapse