Definition

GLC-T is the Cisco 1000BASE-T SFP, which is a fiber optic transceiver module via Category 5 copper lines, Cisco GLC-T fiber transceivers provide 1Gbps data transfer and it provides full-duplex Gigabit Ethernet connectivity to high-end workstations and between wiring closets over existing copper network infrastructure. GLC-T SFP is compliant to IEEE 802.3 and its dimension is 0.6 in x 2.8 in x 0.6 in. GLC-T is with plug in module type Mini-GBIC.

SFP-GE-T is Cisco fiber optic transceiver that works with 1000BASE-T. SFP-GE-T is with extended working temperature and it is with DOM support. SFP-GE-T is small form transceiver with RJ45 connector interface and it is with spring latch for high density applications.

Difference

GLC-T, Cisco compatible copper SFP transceiver module for Category 5 copper wire, RJ-45 connector.SFP-GE-T, 1000BASE-T SFP transceiver module for Category 5 copper wire, extended operating temperature range, RJ-45 connector

Applications

Cisco GLC-T fiber transceivers provide 1Gbps data transfer and it provides full-duplex Gigabit Ethernet connectivity to high-end workstations SFP-GE-T is small form transceiver with RJ45 connector interface and it is with spring latch for high density applications.

GLC-TE

It provides customized and cost-effective solutions of high quality for all needs and specifications, including Optical design, Mechanical design, Printed Circuit Board (PCB) layout and Electrical design, Software & Firmware design, Integrated assembly, Specific labels, etc. 

NEBS  level 3

NEBS (Network Equipment-Building System) describes the environment of a typical United States RBOC Central Office. NEBS is the most common set of safety, spatial and environmental design guidelines applied to telecommunications equipment in the United States. It is an industry requirement, but not a legal requirement.

NEBS Level 3 regulates a lot of stresses including:

1. Fire resistance

2. Thermal margins

3. Acoustic limits

4. Proper airflow

5. Vibration resistance (like earthquakes)

6. RF tolerances and emissions

7. Failover capabilities

Conclusion

The devices can take greater stresses with less likelihood of failure, and are therefore a bit more trustworthy in truly mission-critical applications. However, this also means that the NEBS-ready SFP-GE-T Transceivers are also somewhat more expensive the GLC-T alternative.

Specifications for GLC-T, GLC-TE and SFP-GE-T

By access to Cisco’s relative information, specifications for Cisco GLC-T, GLC-TE and SFP-GE-T are concluded in the table below:

SFP Models	Description	Operating Temperature Range
Cisco GLC-T	1000BASE-T SFP Copper RJ-45 100m Transceiver	COM
Cisco GLC-TE	1000BASE-T SFP Copper RJ-45 100m Transceiver	NEBS 3 ESD EXT
Cisco SFP-GE-T	000BASE-T SFP Copper RJ-45 100m Transceiver	EXT

From the table above, we can see that the difference between GLC-T and GLC-TE is the operating temperature range. Operating temperature range for GLC-T and GLC-TE is respectively commercial temperature range (COM) and Extended temperature range (EXT). The difference between SFP-GE-T and GLC-TE is that the SFP-GE-T has the function of NEBS 3 ESD. 

Distinguishing Between Cisco SFP-GE-T and GLC-T SFP Formats

On the face of it, the two formats are pretty similar and, most of the time, are interchangeable. Both are:

• 1000BaseT 
• RJ45-Based
• Good for up to 100m Ethernet cables
• Gigabit-speed with 10/100 compatibility
• Useful in the same temperature ranges (0-70C)

So in other words, they're both fairly basic Gigabit Ethernet SFP ports, and both should work fine with any standard GbE cabling.  For 99% of Cisco network operators, either could be used with no problems.

Which One Should I Use: GLC-T, GLC-TE and SFP-GE-T

In terms of Cisco original GLC-T, GLC-TE and SFP-GE-T transceivers, GLC-T and SFP-GE-T will be End-of-Sale in June 1, 2017 and replaced by the GLC-TE. So then you can only buy GLC-TE transceivers from Cisco. If you’re dealing directly with a company like a telecom who specifically requires NEBS compliance, they’ll let you know and you should choose SFP-GE-T. But for the most of the networks, GLC-T and GLC-TE transceivers are all you’d need for Gigabit Ethernet, and they cost less as well. Fiberstore (FS.COM) provides all these three SFP modules. We are manufactured to the exact same standards as Cisco’s own brand, and come with true lifetime warranties. Every SFP module in Fiberstore was tested to ensure 100% compatibility, but only cost a small fraction of name-brand alternatives.