​Understanding the CB-LC-LC-SMF20M= Cable​

The ​​CB-LC-LC-SMF20M=​​ is a ​​20-meter single-mode fiber (SMF) optic cable​​ with ​​LC duplex connectors​​ on both ends, engineered for high-speed, long-distance data transmission in Cisco networks. It supports ​​10G/40G/100G Ethernet​​ and is designed for scenarios requiring minimal signal loss over extended ranges, such as connecting switches across buildings or linking core network layers.


​Key Technical Specifications​

  • ​Fiber Type​​: ​​OS2 single-mode​​ (9/125µm), optimized for 1310nm and 1550nm wavelengths.
  • ​Max Distance​​: ​​10km at 10G (10GBase-LR)​​ / ​​40km at 10G (10GBase-ER)​​ with compatible transceivers.
  • ​Connector Quality​​: Ultra-polished LC connectors with ≤0.2dB insertion loss.
  • ​Jacket Rating​​: OFNP (plenum-rated) for fire safety in ductwork or ceiling spaces.

​CB-LC-LC-SMF20M= vs. Multimode Fiber: Core Differences​

​Feature​ CB-LC-LC-SMF20M= (SMF) Multimode Fiber (MMF)
​Distance​ 10km+ (10G) Up to 400m (40G, OM4)
​Cost​ Higher laser transceivers Lower VCSEL-based optics
​Application​ Metro/core networks Data center intra-rack links
​Bandwidth​ Virtually unlimited Limited by modal dispersion

​Why 20 Meters Matters for Single-Mode Deployments​

  1. ​Inter-Building Connectivity​​: Links switches in adjacent structures (e.g., campus networks) without exceeding attenuation budgets.
  2. ​Avoiding Signal Overkill​​: Using 10km-capable cables for short runs (<100m) wastes transceiver power, but 20M strikes a balance for mid-range needs.
  3. ​Future-Proof Scaling​​: Supports upgrades to ​​DWDM (Dense Wavelength Division Multiplexing)​​ for terabit-level capacity on existing fiber paths.

For Cisco-certified compatibility, source the cable from authorized suppliers like [“CB-LC-LC-SMF20M=” link to (https://itmall.sale/product-category/cisco/).


​Field-Tested Perspective​

In a recent deployment for a hospital network, the CB-LC-LC-SMF20M= connected a Nexus 9500 core switch to a storage cluster 15 meters away across EMI-heavy electrical rooms. Single-mode’s immunity to interference ensured zero packet loss, whereas multimode would’ve required costly shielding. A common pitfall: underestimating bend radius. Even slight kinks in 20M runs can spike loss—always use slack loops. While SMF costs more upfront, its lifespan and upgrade potential justify the investment for mission-critical links. Sometimes, “short” runs need long-haul optics.

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