GLC-LH-SMD - Cisco SFP Module 1000BASE-LX/LH long-wave with DOM

Cisco GLC-LH-SMD — 1000BASE-LX/LH SFP Fiber Transceiver (with DOM)

What it is

GLC-LH-SMD is a Cisco SFP (Small Form-Factor Pluggable) fiber transceiver that supports 1 Gbps (1000BASE-LX/LH) long-reach fiber links over single-mode fiber. It includes DOM (Digital Optical Monitoring) for real-time link diagnostics and is designed for use in switches, routers, and industrial gear with SFP ports.

Why buyers pick GLC-LH-SMD (plain English)

Gigabit fiber uplinks: Provides reliable 1 GbE fiber connectivity between closets, buildings, or campus nodes.

Long-reach single-mode fiber: Works over single-mode fiber (SMF) for distances significantly longer than multimode optics allow.

DOM support: Digital Optical Monitoring lets you see live optical signal metrics (like transmit/receive power) for troubleshooting and link health.

Standard SFP form factor: Fits into any compatible SFP port on Cisco networking gear.

60-second spec box (GLC-LH-SMD)

Form factor

• SFP (Small Form-Factor Pluggable)

Speed / protocol

• 1000BASE-LX/LH (1 Gbps fiber)

Fiber type

• Single-mode fiber (SMF)

Wavelength

• 1310 nm

DOM

• Digital Optical Monitoring supported

Connector

• LC duplex

Distance

• Typically up to kilometers depending on fiber type and optics class

Where it fits (and when to choose something else)

Perfect for:

• Long-distance fiber uplinks (between buildings or campus sites)

• Enterprise backbone or aggregation links

• Environments needing optical diagnostics for link health

Choose something else if:

• You only need short multimode fiber → use SX optics

• You need higher throughput → 10G/25G SFP+ / SFP28 modules

• You want copper connections → use 1G copper SFP or RJ-45

TL;DR

GLC-LH-SMD is a Cisco 1000BASE-LX/LH single-mode SFP with DOM — a long-reach Gigabit fiber transceiver with diagnostic monitoring for enterprise links.