FAQs You May Ask When Using 1000BASE-LX/LH SFP

There are many types of fiber optic transceiver used in fiber optic transmission. 1000BASE-LX/LH SFP, one of the commonly used optical transceiver, is now widely used in optical network systems. Here are some common questions we might have when using Cisco 1000BASE-LX/LH SFP (GLC-LH-SM or GLC-LH-SMD) transceivers. And from the answers, we might have a deeper understanding of using these fiber optics.
Q1: Can 1000BASE-LX compatible with 100BASE-LX?
A1: 1000BASE-LX and 100BASE-FX are very different standards. 1000BASE-LX SFP (GLC-LH-SMD) and 100BASE-LX SFP (GLC-FE-100LX) are 2 module types, one for GE and one for FE slots. The GLC-LH-SMD will not operate at 100Mbps. You will need to use a 100Mb module to connect to another device at 100Mb. Check optical transceiver compatibility with your equipment by reviewing the Cisco Fast Ethernet SFP module compatibility document and choose the one it says is compatible.
Q2: What is the difference between LH and LX modules?
A2: Long Haul (LH) denotes longer distances while Long Wavelength (LX) denotes less energy which is obviously shorter distance. Before it was standardized 1000BASE-LX10 was essentially already in widespread use by many vendors as a proprietary extension called either 1000BASE-LX/LH or 1000BASE-LH.
Q3: Does 1000BASE-LX SFP work with 1000BASE-LH SFP? What does it infer if a module says like "Cisco 1000BASE-LX/LH SFP"?
A3: Yes, the 1000BASE-LX will work with the 1000BASE-LH. For instance, Cisco 1000BASE-LX/LH SFP is either made for single mode (long distance) / multimode (short distance). But this module can be used for both Single-mode and Multimode. The Cisco 1000BASE-LX/LH SFP, compatible with the IEEE 802.3z 1000BASE-LX standard, operates on standard single-mode fiber-optic link spans of up to 10 km and up to 550 m on any multimode fibers. When used over legacy multimode fiber type, the transmitter should be coupled through a mode conditioning patch cable.
Q4: What about Mode Conditioning Patch cords (MCP)?
A4: When selecting an optical transceiver, watch the transceiver’s user documentation for when a MCP should be used (see previous link for MCP information). They are sometimes required when your network’s installed optical cable is OM1 or OM2 rated multimode fiber (MMF). In short, the MCP is an optical jumper that transitions the transmit fiber from a single mode fiber (SMF) to a multimode fiber.
Q5: GLC-LH-SM SFP to 1000BASELX GBIC won't link over MMF?
A5: Cisco compatibility document says: "Some customers might be tempted to connect 1000BASE-LX/LH devices over short reaches of MMF jumper cables without MCP cables. There is a risk associated to this type of nonstandard deployment, 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 (typically 5 to 6 dBm), and if the jumper cable is short, the adjacent receiver will be saturated, causing high bit error rate, and eventually irreversibly damaged. We recommend the use of MCP, but if the customer remains reluctant to the deployment of MCP, a 5-dB attenuator for 1300nm should be used and plugged at the transmitter of the optical module on each side of the link."
Q6: Does GLC-LH-SMD working with GLC-LH-SM?
A6: Yes. Both the GLC-LH-SM and GLC-LH-SMD transceivers support the IEEE 802.3 1000BASE-LX/LH standard and so are compatible with each other. The difference between the two is that the GLC-LH-SMD transceiver has additional support for Digital Optical Monitoring capability.
Q7: How much bandwidth can my single mode fiber (SMF) support?
A7: Single mode fiber has an extremely large bandwidth capacity. The following diagram shows how bandwidth can be scaled on SMF. Scaling bandwidth on fiber is not inexpensive. Depending upon the network, it may be more cost effective to install additional fibers instead of adding WDM technology.
Click through to browse GLC-LH-SMD price
Reference: www.sfp-transceiver-modules.com
Warm Tips: Fiberstore offers amount of in-stock 1000BASE-LX/LH SFP which are compatible for Cisco, Juniper, Dell, Finisar, Brocade, or Netgear (AGM732F) in 10/20 Km options.