GLC-LH-SM or SPF-GE-L: What’s the Difference?

GLC-LH-SM and SPF-GE-L are both Cisco based 1000BASE-LX SPF transceivers.  Due to similar specifications of performance and mode of operation like supporting distance and working wavelength, users find it difficult to make a decision while choosing either of these SPF modules.  Well, the major difference between two is that SPF-GE-L support DOM (DIGITAL OPTICAL MONITORING) and GLC-LH-SM doesn’t. However, we will be throwing some light on both in the next post.

GLC-LH-SM SPF Module

The Cisco GLC-LH-SM is a Duplex SFP package transceiver for optical communications, rated for transmission distance up to 10km and a maximum bandwidth of 1Gbps. The GLC-LH-SM transceiver operates at 1310nm wavelength. Complies with SFP MSA and IEEE 802.3Z 1000BASE-LX standards. It can operate up to 550m on any multimode fibers and up-to 10km for single-mode fiber  optic  spans.

GLC-LH-SM Features:

1. Package: SPF 1000 Base- LX/LH Ethernet
2. Transmission distance: Up-to 10km over SMF
3. Wavelength: 1310nm Duplex SPF
4. Operating Case Temperature Range: 0°c to 70°c
5. Sensitivity: < -23dBm
6. Transmit Power: -3dBm
7. RoHS Compliant: Yes
8. Dom Support: No

SFP-GE-L SFP Module

The Cisco SPF-GE-L is also from Cisco family and has many similarities with LH-SM transceiver. Same Cisco based 1000BASE-LX/LH and is designed for Gigabit Ethernet applications. Complies with SFP MSA and IEEE 802.3Z 1000BASE-LX standards.  It can operate up to 550m on any multimode fibers and up-to 10km for single-mode fiber  optic  spans.

GLC-LH-SM Features:

1. Package: SPF 1000 Base- LX/LH Ethernet
2. Transmission distance: Up-to 10km over SMF
3. Wavelength: 1310nm Duplex SPF
4. Operating Case Temperature Range: -5°c to 85°c
5. Sensitivity: < -23dBm
6. Transmit Power: -3dBm
7. RoHS Compliant: Yes
8. Dom Support: Yes

GLC-LH-SM or SPF-GE-L: What’s the Difference?

As per Cisco official website, both GLC-LH-SPF AND SPF-GE-L have been declared as end-of-life since March 8, 2013. Surprisingly, this hasn’t affected the market as customers with active services are promised to receive support from the Cisco Technical Assistance Center (TAC).  Lets clear the confusion regarding the differences between these two.

The first major difference is that SPF-GE-L support DOM (digital optical monitoring) while the other doesn’t.  Does Dom matter for a fiber optic transceiver? The answer is definitely, Yes.  DOM is a very important feature for any fiber optic transceiver. It helps to monitor parameters such as optical input and output power, temperature etc. The second difference is the operating temperature. GLC-LH-SM can bear from (0°c to 70°c), SFP-GE-L has a range of (5°c to 85°c).  

GLC-LH-SM vs. SFP-GE-L: Which One is best for you?

From the above discussions, one can conclude that both of them can be used as one type module. But still, there are some differences for some applications. As WS-SUP32-8GE-3B does not support DOM SFP modules like the SFP-GE-L while supporting GLC-LH-SM SFP. I hope this article will help you choose the best model for your applications. GLC-LH-SMD is the replacement of GLC-LH-SM and it supports the DOM interface. On other hand GLC-LX-SM-RGD has all features of SPF-GE-L and has a wider operating temperature of (-40~85°C).