Do you know the difference between GLC-T, GLC-SX-MM & GLC-SX-MMD?

GLC-T, GLC-SX-MM, and GLC-SX-MMD are commonly used in Cisco network equipment for short-range applications, but many IT managers are confused about the specification and do not know the difference between them. Today, let’s turn to this topic and compare them to help you understand the differences. Please note that all of the following information is for reference only and it is recommended that you purchase the original transceiver directly from Cisco or its distributors. First, we’d better understand some basic information that helps us classify differences.

What is GLC-T?

The GLC-T is typically used as the part number for the Cisco 1000BASE-T SFP module. It is also part number of a compatible 1000BASE-T SFP copper RJ-45 100m transceiver with the same features and performance as many other third-party vendors and vendors. It is designed for Gigabit Ethernet connectivity over Cat5e copper. The GLC-T allows users to connect to the network port and a high-performance Ethernet network. It allows you to achieve Gigabit Ethernet speeds with your existing infrastructure, providing a convenient and cost-effective solution for your network needs.

What is GLC-SX-MM?

The GLC-SX-MM typically represents the Cisco 1000BASE-SX short-wavelength SFP module. It is also the part number of a compatible 1000BASE-SX SFP transceiver with the same features and performance as many other third-party vendors. It is a 1000BASE-SX SFP transceiver that allows users to use existing cable runs up to 550 meters on 50/125, 250M 62.5 / 125 and 1km 50/125 OM3 cables.

What is GLC-SX-MMD?

The GLC-SX-MMD is one of the most popular standard Cisco SFPs and is a hot-swappable I/O device that plugs into a Gigabit Ethernet port. It is an improved version of the GLC-SX-MM that includes digital optical monitoring (DOM) that monitors the state of the transceiver. These transceivers operate from multimode fiber (MMF) up to 550 meters.

What is the difference between GLC-T, GLC-SX-MM, and GLC-SX-MMD?

Exterior the same the same the same
Transceiver type SFP transceiver SFP transceiver SFP transceiver
wavelength copper 850 nm 850 nm
achieve 100 meters 550 meters 550 meters
Fiber type Cat 5 Multimode fiber (MMF) Multimode fiber (MMF)
Connector type LC duplex LC duplex LC duplex
Data rate 1000 Mbps 1.25 Gbps 1.25 Gbps
Wiring type Ethernet 1000Base-T Ethernet 1000Base-SX Ethernet 1000Base-SX
DOM support No Yes No
Operating temperature 0°C to 70°C (commercial grade) 0°C to 70°C (commercial grade) 0°C to 70°C (commercial grade)
Storage temperature -40°C to 85°C -40°C to 85°C -40°C to 85°C
energy consumption 1.0 W 0.8 watt 0.8 watt
weight 0.025 kg 0.025 kg 0.025 kg
Price (third party replacement) US $ 13.00  US $ 6.00  US $ 6.00 


From the above comparison, we know that the GLC-T is a standard 1000Base-T SFP module that can only be used with Cat cables up to 100 meters away. The GLC-SX-MM is an old 1000BASE-SX SFP transceiver without DOM functionality. It has been discontinued and is now upgraded to the DOM-enabled GLC-SX-MMD. Optcore offers third-party SFP transceivers that are 100% compatible with GLC-T, GLC-SX-MM, and GLC-SX-MMD at the best price and high quality.

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