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1 A mode conditioning patch cord may be needed for some Gigabit-LX installations. See “Mode Conditioning Patch Cord” on page A-5 for more information. Specifications Cabling and Technology Information Note on 1000BASE-T Cable Requirements. The Category 5 networking cables that work for 100BASE-TX connections should also work for 1000BASE-T, as long as all four-pairs are connected. But, for the most robust connections, you should use cabling that complies with the Category 5e specifications, as described in Addendum 5 to the TIA-568-A standard (ANSI/ TIA/EIA-568-A-5). Because of the increased speed provided by 1000BASE-T (Gigabit-T), network cable quality is more important than for either 10BASE-T or 100BASE-TX. Cabling plants being used to carry 1000BASE-T networking must comply with the IEEE 802.3ab standards. In particular, the cabling must pass tests for Attenuation, Near-End Crosstalk (NEXT), and Far-End Crosstalk (FEXT). Additionally, unlike the cables for 100BASE-TX, the 1000BASE-T cables must pass tests for Equal-Level Far-End Crosstalk (ELFEXT) and Return Loss. When testing your cabling, be sure to include the patch cables that connect the switch and other end devices to the patch panels on your site. The patch cables are frequently overlooked when testing cable and they must also comply with the cabling standards. Technology Distance Specifications Technology Distance Specifications Technology Supported cable type Multimode fiber modal bandwidth Supported distances 100-FX multimode fiber any up to 2,000 meters 1000-T twisted-pair copper N/A up to 100 meters 1000-SX multimode fiber 160 MHz*km 200 MHz*km 400 MHz*km 500 MHz*km 2 - 220 meters 2 - 275 meters 2 - 500 meters 2 - 550 meters 1000-LX multimode fiber single mode fiber 400 MHz*km 500 MHz*km N/A 2 - 550 meters 2 - 550 meters 2 - 10,000 meters Specifications Mode Conditioning Patch Cord Mode Conditioning Patch Cord The following information applies to installations in which multimode fiber- optic cables are connected to a Gigabit-LX port. Multimode cable has a design characteristic called “Differential Mode Delay”, which requires the transmission signals be “conditioned” to compensate for the cable design and thus prevent resulting transmission errors. Under certain circumstances, depending on the cable used and the lengths of the cable runs, an external Mode Conditioning Patch Cord may need to be installed between the Gigabit-LX transmitting device and the multimode network cable to provide the transmission conditioning. If you experience a high number of transmission errors on those ports, usually CRC or FCS errors, you may need to install one of these patch cords between the fiber-optic port in your switch and your multimode fiber-optic network cabling, at both ends of the network link. The patch cord consists of a short length of single mode fiber cable coupled to graded-index multimode fiber cable on the transmit side, and only multimode cable on the receive side. The section of single mode fiber is connected in such a way that it minimizes the effects of the differential mode delay in the multimode cable. No t e Most of the time, if you are using good quality graded-index multimode fiber cable that adheres to the standards listed in this appendix, there should not be a need to use mode conditioning patch cords in your network. This is especially true if the fiber runs in your network are relatively short. Installing the Patch Cord As shown in the illustration below, connect the patch cord to the transceiver with the section of single mode fiber plugged in to the Tx (transmit) port. Then, connect the other end of the patch cord to your network cabling patch panel, or directly to the network multimode fiber. If you connect the patch cord directly to the network cabling, you may need to install a female-to-female adapter to allow the cables to be connected together. Specifications Mode Conditioning Patch Cord TxRxTo network multimode cabling Mode Conditioning Patch Cord The multimode cable in the patch cord must match the characteristics of your network cable Gigabit-LX port Single mode section plugs into Tx port on Gigabit-LX Transceiver or Gigabit-LX mini-GBIC Example: Connecting a Mode Conditioning Patch Cord for Gigabit-LX Make sure you purchase a patch cord that has appropriate connectors on each end, and has multimode fibers that match the characteristics of the multimode fiber in your network. Most important, the core diameter of the multimode patch cord must match the core diameter of the multimode cable infrastructure (either 50 or 62.5 microns). Specifications Twisted-Pair Cable/Connector Pin-Outs Twisted-Pair Cable/Connector Pin-Outs The Auto-MDIX Feature: In the default configuration, “Auto”, the fixed 10/ 100/1000Base-T ports on the switches all automatically detect the type of port on the connected device and operate as either an MDI or MDI-X port, whichever is appropriate. So for any connection, a straight-through twisted- pair...