Cisco GLC-SX-MMD 1000BASE-SX SFP Transceiver Module, MMF (850nm), DOM

Cisco GLC-SX-MMD is a high-performance, hot-swappable SFP (Small Form-factor Pluggable) transceiver module designed for Gigabit-Ethernet deployments over multimode fiber. It supports the IEEE 802.3z 1000BASE-SX standard and enables cost-effective fibre links within enterprise, data-centre and wiring-closet environments. With a nominal wavelength of 850 nm, LC-duplex fibre connector, digital-optical monitoring (DOM) capability and support for link spans up to 550 m on 50 µm MMF, this module lets network administrators extend or upgrade their fibre connectivity while maintaining robust Cisco-platform compatibility.

Product Features

Hot-Swappable SFP Form Factor

The GLC-SX-MMD module can be inserted or removed from a compatible host device without powering down the system, minimizing network downtime and simplifying serviceability.

Multimode-Fibre (MMF) Support at 850 nm

This transceiver operates on the 850 nm wavelength over multimode fibre (MMF) and supports link distances of up to 220 m on 62.5/125 µm FDDI-grade fibre, up to 275 m on 62.5/125 µm OM1, and up to 550 m on 50 µm OM2 fibre.

Digital Optical Monitoring (DOM) / Digital Diagnostics

Supports Digital Optical Monitoring (DOM) capability (also known as DDM) to provide real-time access to operating parameters such as optical output power, receive power, transceiver temperature and supply voltage — useful for proactive link monitoring.

Broad Platform Compatibility

Designed to be compatible with a wide range of Cisco switches, routers and other network equipment that support SFP ports — enabling flexibility in media type choice (copper, MMF, SMF) on a port-by-port basis.

Product Specifications

• Form factor: SFP (Small Form-factor Pluggable)
• Standard: IEEE 802.3z 1000BASE-SX
• Wavelength: 850 nm nominal
• Fibre type: Multimode fibre (MMF)
• Connector: LC duplex (dual LC/PC)
• Supported link distances (example specifications):
  • ~220 m on 62.5 µm FDDI-grade MMF
  • ~275 m on 62.5 µm OM1 MMF
  • ~500-550 m on 50 µm OM2 MMF (may vary depending on fibre quality)
• Power supply: +3.3V typical (SFP standard)
• Operating temperature: Standard 0 °C to 70 °C; extended/industrial variants (-40 °C to +85 °C) may exist.

Usage & Deployment Tips

• Ensure the host SFP port supports the GLC-SX-MMD or equivalent Cisco-certified optics; verify compatibility via the switch/router vendor compatibility list.
• Use appropriate MMF cabling: verify fibre type (OM1, OM2, OM3) and end-face cleanliness and ensure patch cords/connectors are in good condition to achieve the specified distances.
• For runs beyond ~550 m or for future-proofing, consider single-mode fibre (SMF) transceivers instead.
• Monitor the module via DOM/diagnostics to catch issues such as signal degradation or overheating.
• Insert the module into the host while the port is disabled or idle if possible, and verify link establishment and speed negotiation once connected.