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Fiber Optic Transceivers Classification And Technical Notes



Divided by rate, fiber optic transceivers can be divided into 10M, 100M fiber optic transceivers, 10 / 100M adaptive 1000M fiber optic transceivers and fiber optic transceivers.

     10M and 100M transceiver products work at the physical layer, in this layer transceiver products are working to forward the data bit. The forwarding has forwarded speed, high permeability, low latency advantages of aspects in terms of better compatibility and stability, the fixed rate applies for the link. The 10 / 100M fiber optic transceiver is working in the data link layer, using store and forward mechanism in this layer optical transceivers, so each packet forwarding mechanism should read it received the source MAC address, destination MAC address, and after the completion of CRC cyclic redundancy check before forwarding the packet out. Store and forward the benefits that it can prevent the spread of some erroneous frames in the network, taking up valuable network resources, but also can be a good way to prevent packet loss due to network congestion. When the data link saturation can not be forwarded store and forward data to the cache on the transceiver, and then forwards the network is idle while waiting. This not only reduces the possibility of data conflicts and ensure the reliability of data transmission, so 10 / 100M fiber optic transceivers suitable for working in the rate is not fixed link.

     According to the structure points, can be divided into desktop (standalone) rack-mounted fiber optic transceivers and fiber optic transceivers.

     Desktop fiber optic transceivers suitable for a single user, such as a single switch in the corridor of the Alliance met. Rack-mounted fiber optic transceiver for multi-user aggregation, such as the center of the room on a cell within a cell linked all the switches must be met, use a rack to facilitate unified management and unified power of all fiber-optic transceiver modules.

     By optical fiber to points, can be divided into multi-mode fiber optic transceivers and single-mode fiber transceiver.

     Due to the use of different fiber transceivers can transmit distances are not the same, multimode transceivers general transmission distance between 2 km to 5 km, while the range of single-mode transceiver coverage from 20-120 km. It should be noted that due to different fiber transceiver transmission power itself of the transmission distance, and the reception sensitivity wavelength will be different. 5 km fiber optic transceiver transmitting power generally between -20 ~ -14db, receiver sensitivity is -30db, using 1310nm wavelength; and 120 kilometers of fiber optic transceivers transmit power more in between -5 ~ 0dB, receiver sensitivity -38dB, using a wavelength of 1550nm.

     According to the number of fiber to points, can be divided into single-fiber optical transceiver, and dual-fiber fiber optic transceivers.

     As the name suggests, the device can save half of the single-fiber, namely to achieve receive and transmit data over a single fiber, the fiber is very suitable place resource constraints. Such products using WDM technology, the use of multi-wavelength is 1310nm and 1550nm. But because there is no unified single fiber transceiver products of international standards, products from different vendors during interoperability incompatibilities may exist. Also due to the use of wavelength division multiplexing, single fiber transceivers ubiquitous large signal attenuation characteristics. Currently on the market for fiber optic transceivers more dual-fiber products, such products are more mature and stable.

     Managed by points, can be divided into managed and unmanaged fiber optic transceivers fiber optic transceivers.

     With operable and manageable network toward the direction of development, most operators want their network to all devices are able to do the degree of remote network management, fiber optic transceivers and switches, routers, like progressive development in this direction. Most vendors of network management systems are based on SNMP network protocol developed by a variety of management support, including Web, Telnet, CLI, etc. Manage more content, including configuration mode fiber optic transceivers, fiber optic transceiver module monitor type, work status, chassis temperature, power supply, the output voltage and output optical power and so on. As operators of the need for more and more network equipment, fiber optic transceivers, network management believes will become more practical and intelligent.

     Fiber optic transceiver on the limitations of the data transmission broke the meter Ethernet cable, relying on high-performance and high-capacity switching chip cache, while the truly non-blocking switching performance transmission, also provides balanced flow, isolation and conflict error detection and other functions, to ensure high safety and stability data transmission. So in a very long time fiber optic transceiver products will continue to be set up in the actual network indispensable part of the future of fiber optic transceivers will move toward high intelligence, high stability, managed, low-cost orientation continue to develop.

  A typical type of transceiver interface Ethernet interface, E1 interface, serial interface (RS232), SC / ST interface, USB interface.

     1. Ethernet Interface

         Interface Standard: IEEE802.3

         Terminal velocity: 10M / 100 / 1000Mbps

         Mode: Full-duplex, half-duplex

         Terminal Connector: RJ45 interface

     2. E1 interface

         Network interface: G.703, G.704, G.823

         Network speed: 2.048Mbps

         Network Connector: BNC (75 Ohm), etc.

         Line coding: HDB3 code

     3. Serial Interface

         Interface rate: 19200bps

         Interface Standard: RS-232

     4. SC / ST interface

         ST Interface: 10Base-F

         SC interface: 100Base-FX

     5. USB interface

         USB1.1: 12Mbps

         USB2.0: 480Mbps

Local Area Network (LAN) There are three main types of structures: Ethernet (Ethernet), Token Ring (Token Ring), token bus (Token Bus) as well as the three network backbone FDDI (FDDI). They are followed by IEEE (American Association of Electrical Engineers) standard developed by the beginning of the 802, there are currently 11 and LAN-related standards, they are:

      IEEE 802.1── common networking concepts and bridges, etc.

     IEEE 802.2── LLC etc.

     IEEE 802.3──CSMA / CD access method and physical layer requirements

     IEEE 802.4──ARCnet bus structure and access method, physical layer requirements

     IEEE 802.5──Token Ring Access Method and Physical Layer requirements, etc.

     IEEE 802.6── access method and physical layer requirements MAN

     Broadband LAN IEEE 802.7──

     IEEE 802.8── fiber LAN (FDDI)

Different transceivers convert different products due to the transmission rate of the interface is different, typical interface transfer rate as follows:

Due to the use of different media, the transceiver can transmit distances are not the same, multimode transceivers general transmission distance between 2 km to 5 km, while the range of single-mode transceiver coverage from 20-120 km. It should be noted that due to different fiber transceiver transmission power itself of the transmission distance, and the reception sensitivity wavelength will be different. 5 km fiber optic transceiver receiver sensitivity of -30dB, using 1310nm wavelength; and receiver sensitivity 120 kilometers of fiber optic transceivers for -38dB, using 1550nm wavelength.

Fiber optic transceiver is a twisted pair electrical short distance and long-distance optical signal transmission swap Ethernet media conversion unit, in many places, also known as the photoelectric converter or fiber optic converter (Fiber Converter ).

     Fiber Optic Transceiver general application can not be covered in the Ethernet cable must be used to extend optical fiber transmission distance of the actual network environment while helping the last-mile fiber-optic lines connected to the metro and more outer network also played a huge role. With fiber optic transceivers, but also for the need to upgrade from copper to fiber, but the lack of user funding, manpower or time to provide a low-cost solution. In order to ensure the card is fully compatible with other manufacturers, repeaters, hubs, and switches and other network equipment, fiber optic transceiver products must strictly comply with 10Base-T, 100Base-TX, 100Base-FX, IEEE802.3 Ethernet and IEEE802.3u etc. network standards. In addition, the EMC electromagnetic radiation areas shall comply with FCC Part15. Nowadays due to major domestic carriers are vigorously building community networks, campus networks and enterprise networks, and therefore the amount of fiber optic transceiver products are constantly improved to better meet the needs of the construction of the access network.

     Fiber optic transceivers typically have the following basic characteristics:

1. Provide ultra-low latency data transfer.

     2. Completely transparent to the network protocol.

     3. Using a dedicated ASIC chip wire-speed forwarding data. Programmable ASIC will centralize multiple functions on a single chip, with a simple design, high reliability, low power consumption, etc., enabling the machine to get higher performance and lower cost.

     4. Rack-mount device provides hot-swappable capabilities, ease of maintenance and upgrades without interruption.

     5. Managed devices can provide network diagnostics, upgrades, status reports, exception reporting and control functions that can provide complete operation log and alarm log.

     6. Equipment use more 1 + 1 power supply design, and support wide supply voltage to achieve power protection and automatic switching.

     7. Support wide operating temperature range.

     8. Support the full range of transmission distance (from 0 to 120 km)