The small form-factor pluggable (SFP) transceiver was jointly developed by many of the world's leading network vendors, and it is now widely used in optical network systems. The SFP module was designed under the Multi-Source Agreement (MSA) which meant that the specification for the interface and electrical operation were standardised between vendors.

Here are some common questions we might have when using SFP transceivers. And from the answers, we might have a deeper understanding of using these SFP optics.

Can I pair different types of SFP transceivers?

No. You should use the same type of SFP transceiver at both ends.

What type of optical fiber cable should I use with these SFP modules?

You should use an optical fiber cable with LC connector, which is also known as LC fiber patch cable.

Are the Mini-GBICs and SFPs hot-swappable?

Yes, all Mini-GBICs and SFPs are hot-swappable (they can be installed and removed while the switch is powered on). However, the network cable should be disconnected before removing the Mini-GBIC or SFP from the switch.

Best practice tip: After inserting a transceiver into a switch, the Mode LED will come on for two seconds while the transceiver is initialized. Do not remove the transceiver until the Mode LED has turned off.

What does 1000BASE-T or 1000BASE-X mean?

This designation is defined in IEEE802.3: 2002. The "1000" in the designation refers to the transmission speed of 1000 Mbps. The "BASE" refers to BASE band signaling, indicating that only Ethernet signals are carried on the medium. The "T" represents twisted-pair copper cable (for example Ca t 5), and the "X" represents fiber optic cable.

Will compatible SFP transceivers affect my host device warranty?

No, host device warranties will be unaffected. Please note that host device warranties do not cover SFP transceiver modules, OEM vendors offer lifetime warranties to protect these.

How does transceiver compatibility work?

Each module holds its own information in EEPROM; this memory is coded with unique identifiers such as part numbers and manufacturers details. The firmware of the host device then checks the memory for the correct information to confirm compatibility.

What is DOM support?

Digital optical monitoring (DOM) is a feature which allows you to monitor many parameters of the transceiver module in real-time. DOM allows you to monitor the TX (transmit) and RX (receive) of the module, as well as input/output power, temperature, and voltage. Network administrators can then check and ensure that the module is functioning correctly.

Does GLC-SX-MMD working with GLC-SX-MM?

Yes. Both the GLC-SX-MM and GLC-SX-MMD transceivers support the IEEE 802.3 1000BASE-SX standard and so are compatible with each other. The difference between the two is that the GLC-SX-MMD transceiver has additional support for DOM capability.

Why does my compatible SFP not work with the host device?

This is a common problem, a large amount of host devices do not have a firmware check for compatibility, this is known as an "open platform". Many SFP transceivers are sold as compatible when in fact they are open platform, they will work in many host devices but not in any that require coded transceivers. OEM SFP transceivers are coded specifically to suit each host device to avoid this problem. Even HP's range of J4859C and HP JD118B SFPs are covered.

How to Identify The Refurbished SFP Transceiver Module

Here are three methods to identify the refurbished SFP transceiver module:

• Appearance recognition. Check the appearance of the SFP transceiver modules: new SFP module's appearance generally has good consistency while the refurbished SFP module is not glossy, and have some wear and scratches in the rim angle. Many refurbished SFP modules are replaced with a new shell, in this case, we can see the interface of the modules, if there is dust and not smooth, it is the refurbished modules.
• Check the ferrule. Pulled out of the dust cap, we can see the ferrule in the bore. In general, the multimode SFP transceiver has plastic ferrules or metal ferrules while the singlemode SFP transceiver has the metal ferrule. A second-hand old module is lack of glossy, and generally rough and with scratch that has a bad consistency. The ferrules of a new quality module is brightness of color and lustre and has a good consistency.
• Put the modules working under the status of 50-60 °C and see if it is working properly. In generally, a refurbished SFP transceiver module can not work well or even disconnect.

Why Choose a compatible SFPs?

In fact, most of the networking manufacturers including Cisco, HP networking and Juiper do not produce their own SFP, GBIC, XFP, SFP+, XENPAK and X2 transceivers. They buy original equipment manufacturers (OEM) transceivers, labeled with their own brand and sell at a much higher price. You are basically paying a high price to have the respective manufacturers logo on the equipment.

Fiberstore(FS.COM) offers you a compatible transceiver solution at a fraction of the original cost and a 5-year warranty. These products are manufactured per precise OEM specifications and with high quality.

See more at www.sfp-transceiver-modules.com/wiki_list