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Black Box Explains...DIN rail usage.

DIN rail is an industry-standard metal rail, usually installed inside an electrical enclosure, which serves as a mount for small electrical devices specially designed for use with DIN rails. These... more/see it nowdevices snap right onto the rails, sometimes requiring a set screw, and are then wired together.

Many different devices are available for mounting on DIN rails: terminal blocks, interface converters, media converter switches, repeaters, surge protectors, PLCs, fuses, or power supplies, just to name a few.

DIN rails are a space-saving way to accommodate components. And because DIN rail devices are so easy to install, replace, maintain, and inspect, this is an exceptionally convenient system that has become very popular in recent years.

A standard DIN rail is 35 mm wide with raised-lip edges, its dimensions outlined by the Deutsche Institut für Normung, a German standardization body. Rails are generally available in aluminum or steel and may be cut for installation. Depending on the requirements of the mounted components, the rail may need to be grounded. collapse


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

  • Manual... 
  • LinkGain 10/100BASE-TX to 100BASE-FX Media Converter Manual
    Manual for the BMC300-MMST and LBMC300-MMSC (Version 1)
 

Black Box Explains...802.3ah.

802.3ah, also called Ethernet in the First Mile (EFM), is a new Ethernet standard designed to compete with standards such as DSL and cable modem in delivering broadband access to... more/see it nowhomes.

The 802.3ah specification covers point-to-point copper, point-to-point fiber, and point-to-multipoint fiber.

Ethernet in the First Mile over Copper (EFMC)
This point-to-point specification for copper wire takes advantage of DSL technology to send Ethernet over one pair of copper wires at 10 Mbps for 750 meters or 2 Mbps for 2700 meters.

Ethernet in the First Mile over Fiber (EFMF)
This point-to-point specification for single-mode, single-strand or single-mode, duplex fiber sends Ethernet at speeds of 100 Mbps or 1 Gbps up to 10 kilometers. It includes an optional extended temperature range from -40 to 185° F (-40 to 85° C) for outdoor use.

Ethernet in the First Mile over Passive Optical Networks (EPON)
This point-to-multipoint specification for fiber uses an optical splitter to divide the Ethernet signal into separate strands that go to individual subscribers. This enables an ISP to link many subscribers to a single uplink fiber without using active components in the field.

802.3ah includes the OAM specification, which provides utilities for monitoring and troubleshooting Ethernet links remotely, a capability vital for carrier-class deployment. OAM protocols address discovery, link monitoring, remote fault signaling, and remote loopback.

OAM is managed in-band but takes up very little bandwidth so network performance is not noticeably affected. OAM itself is not affected by VLANs or port-access restrictions. collapse


Product Data Sheets (pdf)...FlexPoint Modular Media Converters


Black Box Explains...Layer 2, 3, and 4 switches.



...more/see it now
OSI Layer Physical
Component
7-Application Applicaton Software

LAN-Compatible Software
E-Mail, Diagnostics, Word Processing, Database


Network Applications
6-Presentation Data-
Conversion Utilities
Vendor-Specific Network Shells and Gateway™ Workstation Software
5-Session Network Operating System SPX NetBIOS DECnet™ TCP/IP AppleTalk®
4-Transport Novell® NetWare® IPX™ PC LAN LAN Mgr DECnet PC/TCP® VINES™ NFS TOPS® Apple
Share®
3-Network Control
2-Data Link Network E A TR P TR E TR E E E P E P
1-Physical E=Ethernet; TR=Token Ring; A=ARCNET®; P=PhoneNET®

With the rapid development of computer networks over the last decade, high-end switching has become one of the most important functions on a network for moving data efficiently and quickly from one place to another.


Here’s how a switch works: As data passes through the switch, it examines addressing information attached to each data packet. From this information, the switch determines the packet’s destination on the network. It then creates a virtual link to the destination and sends the packet there.


The efficiency and speed of a switch depends on its algorithms, its switching fabric, and its processor. Its complexity is determined by the layer at which the switch operates in the OSI (Open Systems Interconnection) Reference Model (see above).


OSI is a layered network design framework that establishes a standard so that devices from different vendors work together. Network addresses are based on this OSI Model and are hierarchical. The more details that are included, the more specific the address becomes and the easier it is to find.


The Layer at which the switch operates is determined by how much addressing detail the switch reads as data passes through.


Switches can also be considered low end or high end. A low-end switch operates in Layer 2 of the OSI Model and can also operate in a combination of Layers 2 and 3. High-end switches operate in Layer 3, Layer 4, or a combination of the two.


Layer 2 Switches (The Data-Link Layer)

Layer 2 switches operate using physical network addresses. Physical addresses, also known as link-layer, hardware, or MAC-layer addresses, identify individual devices. Most hardware devices are permanently assigned this number during the manufacturing process.


Switches operating at Layer 2 are very fast because they’re just sorting physical addresses, but they usually aren’t very smart—that is, they don’t look at the data packet very closely to learn anything more about where it’s headed.


Layer 3 Switches (The Network Layer)

Layer 3 switches use network or IP addresses that identify locations on the network. They read network addresses more closely than Layer 2 switches—they identify network locations as well as the physical device. A location can be a LAN workstation, a location in a computer’s memory, or even a different packet of data traveling through a network.


Switches operating at Layer 3 are smarter than Layer 2 devices and incorporate routing functions to actively calculate the best way to send a packet to its destination. But although they’re smarter, they may not be as fast if their algorithms, fabric, and processor don’t support high speeds.


Layer 4 Switches (The Transport Layer)

Layer 4 of the OSI Model coordinates communications between systems. Layer 4 switches are capable of identifying which application protocols (HTTP, SNTP, FTP, and so forth) are included with each packet, and they use this information to hand off the packet to the appropriate higher-layer software. Layer 4 switches make packet-forwarding decisions based not only on the MAC address and IP address, but also on the application to which a packet belongs.


Because Layer 4 devices enable you to establish priorities for network traffic based on application, you can assign a high priority to packets belonging to vital in-house applications such as Peoplesoft, with different forwarding rules for low-priority packets such as generic HTTP-based Internet traffic.


Layer 4 switches also provide an effective wire-speed security shield for your network because any company- or industry-specific protocols can be confined to only authorized switched ports or users. This security feature is often reinforced with traffic filtering and forwarding features.

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Product Data Sheets (pdf)...PCI Fiber Adapters

  • Manual... 
  • Dynamic Fiber Conversion System Desktop Managed Media Converter User Manual
    User Manual for the LMC11032A, LMC11032AE, LMC11042A, & LMC11042AE (Version 1)
 
  • Manual... 
  • AC Module for LMC5207A or LMC5227A High-Density Media Converter System II Chassis User Manual
    User Manual for LMC5210A-R2, LMC5211A, LMC5212A-R2, LMC5214A, and PS7412A (1)
 
  • Manual... 
  • Managed Miniature Media Converters User Manual
    User Manual for the LMM101A-R2, LMM102A-R2, LMM103A-R2, LMM104A-R2, LMM115A, and LMM116A (Version 2)
 
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