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Product Data Sheets (pdf)...10BASE-T UTP Remote MiniBridge

  • Manual... 
  • Miniature Remote Fast Ethernet Bridges
    Installation/User (10/6/2013)

Black Box Explains... Bridges

If you work with legacy networks, you have doubtlessly encountered bridges. Bridges perform the same function as today’s switches in that they connect multiple network segments to create one homogenous... more/see it nownetwork, while keeping each segment isolated from the others.

Bridges operate on MAC-layer addresses and are protocol independent, so they transfer data between workstations without understanding the protocol. Since they don’t have to understand the protocol, they require little or no configuration.

Once you connect the bridge to the network, it automatically learns the addresses of all connected nodes and then creates an internal address table of this information.

When the bridge sees a packet, it checks the packet’s destination address against its internal list. If the address indicates the packet needs to be forwarded, the bridge passes the packet to the appropriate segment. If a bridge doesn’t know where a packet belongs—for example, when a station is first powered on—it passes on the packet.

Bridges can also distinguish between local data and remote data, so data traveling from one workstation to another in the same network doesn’t have to cross the bridge.

Although they are no longer in general use, Black Box stocks bridges for use as replacement parts in legacy networks. Replacing bridges with bridges rather than switches is often preferable because bridges are generally available with the BNC and AUI interfaces often found in older networks. Also, some bridges are able to link to other protocols such as RS-530 and X.21, enabling you to use these media to establish Ethernet network connections. collapse

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  • Manual... 
  • Remote MiniBridge
    Installation/User (Mar-99)

Black Box Explains...Multimode vs. single-mode Fiber.

Multimode, 50- and 62.5-micron cable.
Multimode cable has a large-diameter core and multiple pathways of light. It comes in two core sizes: 50-micron and 62.5-micron.

Multimode fiber optic cable can be... more/see it nowused for most general data and voice fiber applications, such as bringing fiber to the desktop, adding segments to an existing network, and in smaller applications such as alarm systems. Both 50- and 62.5-micron cable feature the same cladding diameter of 125 microns, but 50-micron fiber cable features a smaller core (the light-carrying portion of the fiber).

Although both can be used in the same way, 50-micron cable is recommended for premise applications (backbone, horizontal, and intrabuilding connections) and should be considered for any new construction and installations. Both also use either LED or laser light sources. The big difference between the two is that 50-micron cable provides longer link lengths and/or higher speeds, particularly in the 850-nm wavelength.

Single-mode, 8–10-micron cable.
Single-mode cable has a small, 8–10-micron glass core and only one pathway of light. With only a single wavelength of light passing through its core, single-mode cable realigns the light toward the center of the core instead of simply bouncing it off the edge of the core as multimode does.

Single-mode cable provides 50 times more distance than multimode cable. Consequently, single-mode cable is typically used in long-haul network connections spread out over extended areas, including cable television and campus backbone applications. Telcos use it for connections between switching offices. Single-mode cable also provides higher bandwidth, so you can use a pair of single-mode fiber strands full-duplex for up to twice the throughput of multimode fiber.

Specification comparison:

50-/125-Micron Multimode Fiber

850-nm Wavelength:
Bandwidth: 500 MHz/km;
Attenuation: 3.5 dB/km;
Distance: 550 m;

1300-nm Wavelength:
Bandwidth: 500 MHz/km;
Attenuation: 1.5 dB/km;
Distance: 550 m

62.5-/125-Miron Multimode Fiber

850-nm Wavelength:
Bandwidth: 160 MHz/km;
Attenuation: 3.5 dB/km;
Distance: 220 m;

1300-nm Wavelength:
Bandwidth: 500 MHz/km;
Attenuation: 1.5 dB/km;
Distance: 500 m

8–10-Micron Single-Mode Fiber

Premise Application:
Wavelength: 1310 nm and 1550 nm;
Attenuation: 1.0 dB/km;

Outside Plant Application:
Wavelength: 1310 nm and 1550 nm;
Attenuation: 0.1 dB/km collapse

Results 1-6 of 6 1 



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