GLC-LH-SMD, GLC-LH-SM, SFP-GE-L, and GLC-LX-SM-RGD are predominant kinds of 1000BASE-LX SFP transceiver. seeing that they have got similar specifications, many end customers may be pressured when choosing a 1000BASE-LX fiber SFP module for their Cisco switches. So, How need to we select?
Overview
GLC-LH-SMD is fully compliant with the IEEE 802.3z 1000BaseLX standard. GLC-LH-SMD also uses digital optical monitoring. It reaches 10 km on single-mode fiber (SMF) versus 5 km as specified in the standard.
GLC-LH-SM is1000BASE-LX / LH Small Form Factor Pluggable Transceiver Module for MMF and SMF; with 1300 nm Wavelength and Dual LC / PC Connector.
SFP-GE-L is designed for multimode fiber link up to 550 meters span or 10 km single-mode fiber.
GLC-LX-SM-RGD is 1000BASE-LX/LH long wavelength; rugged SFP transceiver for industrial Ethernet applications.
GLC-LH-SMD vs GLC-LH-SM vs SFP-GE-L vs GLC-LX-SM-RGD, What is the similarities and differences?
Now let us make a comparison of the specifications and compatibility, this article will help you choose the right models depends on your application.
| Models / Specs | Data Rate | Wavelength | Fiber mode | Distance | Connector | DOM | Operating Temperature |
| GLC-LH-SM | 1G | 1310nm | Single mode | 10 km | Duplex LC | No | Commercial 0~70°C |
| GLC-LH-SMD | 1G | 1310nm | Single mode | 10 km | Duplex LC | Yes | Commercial 0~70°C |
| GLC-LX-SM-RGD | 1G | 1310nm | Single mode | 10 km | Duplex LC | Yes | Industrial -40~85°C |
| SFP-GE-L | 1G | 1310nm | Single mode | 10 km | Duplex LC | Yes | Extended -5~85°C |
We can learn the similarity from the above specs comparison, all the four models support same data rate, use the same wavelength, fiber connector and fiber cable for same transmission distance. The main difference is the DOM function (means Digital Optical Monitoring) and operating temperature.
GLC-LH-SMD vs GLC-LH-SM
• GLC-LH-SM is a legacy model, it doesn’t feature DOM function and is EOL, it comes with the lowest price compared with the others.
• GLC-LH-SMD is the replacement of GLC-LH-SM which features an enhanced DOM interface, but with a more expensive price.
SFP-GE-L vs GLC-LX-SM-RGD
• SFP-GE-L also supports DOM, but with an extended temperature -5~85°C for fiber connection application in a harsh environment, of course with a higher cost than GLC-LH-SMD.
• GLC-LX-SM-RGD have all the features that SFP-GE-L support, but provides a wider operating temperature of -40~85°C, it is especially for industrial Ethernet switches.
What about the compatibility?
Most of the Cisco switches and routers support all four models, but please note, some of the switches require different models, you may visit Cisco SFP Compatibility Matrix for more detailed information.