Why My SFP Transceiver Isn't Working?

Updated on May 27, 2021

SFP Transceivers always fail to work because of non-standard operation. When this occurs, it may be a good idea to figure out the reason why the SFP module just isn't working. This guide will assist in supplying a number of solutions for a newbie into the transceiver globe.

The Main Causes of SFP Module Failures

Optical Slots Contamination and Damages

The optical link is not working properly due to contamination and damage to the optical interface. The end face of the fiber connector and optical slots is exposed to the environment and contaminated by dust. Using the scratched or poor-quality fiber connector will cause the SFPs failures.

ESD Damages

ESD is the abbreviation of electrostatic discharge. ESD will absorb dust, change the impedance between lines, and affect the function and life of the product.

Compatibility Issues

Most of the manufacturers guarantee 100% compatibility, which might not be the scenario. Once you find the modules are not compatible, you'll have to troubleshoot them but with no visible outcomes.

How to Use SFP Modules Correctly?

Optical modules must be operated in a standardized manner. Any non-standard operation may result in implicit damage or even permanent failure.

Physical Protection

  • Handle optical modules gently and protect them from falling.

  • When installing an optical module, push it gently by hand. When removing an optical module, unlatch it first. Never use any metal tools during installation and removal.

  • Use a dedicated cotton swab to clean an optical bore and do not insert any metal object into it.

Example for Cleaning a 10G SFP+ Module

ESD Prevention

  • When you transport optical modules, ensure that they are in ESD packages, and do not take them out unless necessary or place them at random.

  • Before touching an optical module, wear an ESD wrist strap or ESD gloves. Take full ESD measures when installing it.

  • Ensure that a device is properly grounded before you test or use it.

  • When plugging in and out non-hot-swap optical module, you should cut off the power.

Avoid Mixed Using

  • The multimode module uses multimode fiber, while single mode module uses single-mode fiber, mixed using will cause signal loss and other failures.

  • All SFP modules should be used in pairs. However, for simplex/BiDi SFPs, we should use two SFPs that have opposite wavelengths for transmitter and receiver.

  • Ordinary SFPs and CWDM/DWDM SFPs can not be mixed using.

  • For long-reach SFPs, because its average output optical power is generally higher than its maximum input optical power, we should pay attention to the length of the optical fiber when installing it. If the condition is not met, then the 10-20db optical attenuator must be used.

  • SFP module's power supply mode is 3.3V. The module will be burnt out if the voltage is increased.

  • When the lower-rate SFP module is used in the higher rate SFPs, error code and video failure will occur. The higher rate SFP module is used at a lower rate, and the transmission distance will be limited.

  • Ensure compatibility match well, all the transceivers have actually a burned-in chip containing information including the serial quantity, the safety information, plus the vendor ID. If the information cannot match what exactly is within the database, these devices will undoubtedly be handicapped making these devices stop working.

FS Compatible 1G SFP Transceiver Module Working on Switch

How Can I Judge If the SFP Module Is Working?

  • Test whether the optical power is within the required range. If there is no light or low optical power, you should check the wavelength and measurement unit (dBm). Clean and check the end face of the optical fiber connector and optical port of the optical module,whether the end face of the optical fiber connector is black ,scratched or bends, and then replace the optical fiber connector or optical module for interchangeability test.

  • The optical power is normal, but the link cannot be connected. Check the link light. This problem pertains to the cabling. The application of bad or wrong cable, wrong cable wiring, or a cable having loops, may lead to this sort of issue.

  • The slot is put in an error-disabled state (corrupted software) after the SFP is inserted, eliminate the SFP transceiver from the slot and change it with an authorized module. If it does not recognize the SFP Module, verify your module just isn’t inserted upside down, check the module slot, or replace an authorized module for interchangeability test.

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