Loading


Categories (x) > Networking > Switches > Commercial/Office Grade (x)

Results 41-50 of 81 < 1 2 3 4 5 > >> 

Product Data Sheets (pdf)...PoE PD Switches

  • Manual... 
  • Unmanaged 802.3at PoE Gigabit Ethernet Switch, 8-Port User Manual
    User Manual for Unmanaged 802.3at PoE Gigabit Ethernet Switch, 8-Port (1)
 

Black Box Explains...PoE phantom power.

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. collapse

  • Firmware... 
  • 28-Port Gigabit Ethernet Managed Switch Firmware
    Firmware for the LGB5028A (Version v2.00)
 
  • Manual... 
  • USB-Powered 10/100 Switch User Manual
    User Manual for the LBS005A and LBS008A (Version 4)
 

Black Box Explains…SFP compatibility.

Standards for SFP fiber optic media are published in the SFP Multi-Source Agreement, which specifies size, connectors, and signaling for SFPs, with the idea that all SFPs are compatible with... more/see it nowdevices that have appropriate SFP slots. These standards, which also extend to SFP+ and XFP transceivers, enable users to mix and match components from different vendors to meet their own particular requirements.

However, some major manufacturers, notably Cisco®, HP®, and 3Com®, sell network devices with SFP slots that lock out transceivers from other vendors. Because the price of SFPs—especially Gigabit SFPs and 10GBASE SFP+ and XFP transceivers—can add significantly to the price of a switch, this lock-out scheme raises hardware costs and limits transceiver choices.

Many vendors don’t advertise that SFP slots on their devices don’t accept standard SFPs from other vendors. This can lead to unpleasant surprises when a device simply refuses to communicate with an SFP.

Another game that some vendors play is to build devices that accept open-standard SFPs, but refuse to support those devices when SFPs from another vendor are used with them.

The only way around this “lock-in” practice is to only buy network devices that accept standard SFPs from all vendors and to buy from vendors that support their devices no matter whose SFPs are used with them. Questions? Call our FREE Tech Support at 724-746-5500. collapse

  • Manual... 
  • PoE PD Switch (Unmanaged, 10BASE-T/100BASE-TX/1000BASE-T) User Manual
    User Manual for the LPDG705A & LPDG708A (Version 3)
 
  • Firmware... 
  • 26-Port Gigabit Managed Switch Firmware
    Firmware for the LGB1126A (Version v2.00)
 
  • Manual... 
  • 100Mb FX Small-Form-Factor %X93plug-in%X94 connector
    Installation and User Guide (Apr-99)
 
  • Quick Start Guide... 
  • Gigabit Smart Switch (Eco Fanless) QSG
    QSG for the LGB2118A & LGB2124A (Version 2)
 
Results 41-50 of 81 < 1 2 3 4 5 > >> 
Close

Support

Delivering superior technical support is our highest priority. Depending on the products or services we provide for you, please visit your appropriate support area.



 

You have added this item to your cart.

Important message about your cart:

You requested more of "" than the currently available. The quantity has been changed to them maximum quantity available. View your cart.

Print
Black Box 1-800-316-7107 Black Box Network Services