When using 1000BASE-LX/LH transceivers with legacy 62.5-micron or 50-micron MMF, you must install a mode-conditioning patch cord between the transceiver and the MMF cable on both ends of the link. According to fiber types of the link like OM1 and OM2, you should decide choose either OM1 Mode Conditioning Patch Cable or OM2 Mode Conditioning Patch Cable. You should never use them for applications over OM3 and more recent fiber types. Mode conditioning cable are normally used in pairs. That means you should need a MCP (Mode conditioning patch) cable at each end to connect the equipment to the cable plant. Next we will introduce the installation steps of the mode conditioning patch cords in Gigabit Ethernet Transmission where the 1000BASE-LX/LH switch is equipped with SCor LC connectors.
How to Install Mode Conditioning Patch Cord?
Step1. Connect the yellow leg (single mode connector) of the MCP cable into the transmit bore of the transceiver.
Step2. Connect the rest orange legs (multimode connectors) of the MCP cable into the receive bore of the transceiver.
Step3. At the other end of the patch cord, put all the orange legs (multimode connectors) into the patch panel.
Step4. Repeat the above three steps for the second transceiver located at the other end of the network link.
After you have finished all the connection steps above, all the swap of transmit and receiver can only be done at the cable plant side.
Mode-conditioning Patch Cord Installation Note:
The requirement for MCP cable is specified only for 1000BASE-LX/LH transceivers transmitting in the 1300-nm window and in applications over MMF. MCP should never be used in 1000BASE-SX links in the 850-nm window.
Another alternative for short reaches within the same location is to use a single-mode patch cable. There will be no saturation over single-mode fiber.
MCP cables are always recommended for a link operating over OM1, OM2 OR FDDI-grade fiber, but never used over OM3 fiber.
There is a risk associated to this type of nonstandard deployment without MCP, especially when the jumper cable is an FDDI-grade or OM1 type. In such case the power coupled directly into a 62.5- micron fiber could be as high as a few dBm and the adjacent receiver will be saturated. This can cause high bit error rate, link flaps, link down status and eventually irreversible damaged to the device.
In the event customers remain reluctant to deploy MCP cables, and for customers using OM3 cables, please measure the power level before plugging the fiber into the adjacent receiver. When the received power is measured above -3dBm, a 5-dB attenuator for 1300nm should be used and plugged at the transmitter source of the optical module on each side of the link.
The benchmark distance of the link distance is 984 feet (300 meters). The MCP cable is required for link distances greater than it.