Black Box Explains...PoE phantom power.
Product Data Sheets (pdf)...Vertical-Mount Managed Fiber Switch
10BASE-T and 100BASE-TX Ethernet use only two pairs of wire in 4-pair CAT5/CAT5e/CAT6 cable, leaving the other two pairs free to transmit power for Power over Ethernet (PoE) applications. However,... more/see it nowGigabit Ethernet or 1000BASE-T uses all four pairs of wires, leaving no pairs free for power. So how can PoE work over Gigabit Ethernet?
The answer is through the use of phantom power—power sent over the same wire pairs used for data. When the same pair is used for both power and data, the power and data transmissions don’t interfere with each other. Because electricity and data function at opposite ends of the frequency spectrum, they can travel over the same cable. Electricity has a low frequency of 60 Hz or less, and data transmissions have frequencies that can range from 10 million to 100 million Hz.
10- and 100-Mbps PoE may also use phantom power. The 802.3af PoE standard for use with 10BASE-T and 100BASE-TX defines two methods of power transmission. In one method, called Alternative A, power and data are sent over the same pair. In the other method, called Alternative B, two wire pairs are used to transmit data, and the remaining two pairs are used for power. That there are two different PoE power-transmission schemes isn’t obvious to the casual user because PoE Powered Devices (PDs) are made to accept power in either format.
100Mb FX Small-Form-Factor %X93plug-in%X94 connector
Installation and User Guide (Apr-99)
Gigabit Managed Switch CLI Guide
CLI Guide for the LGB1108A, LGB1126A, and LGB1148A (Version 1)
Gigabit L3 Managed Switch with 10G Uplinks Accessories Manual
Accessories Manual for the LGB6026A, LGB6050A, LGB6001C, LGB6000SC-001, & LGB6000SC-004 (Version 1)
Unmanaged Gigabit Switch
10-Port Gigabit Managed Switch Firmware
Firmware for the LGB1108A (Version v2.00)
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
- Quick Start Guide...
Gigabit Smart Switch (Eco Fanless) QSG
QSG for the LGB2118A & LGB2124A (Version 1)