40G Cisco Compatible

Cisco®QSFP-40G-ER4 Compatible 40G ER4 QSFP+ Transceiver SMF 1310nm 40km LC DOM
Cisco®QSFP-40G-ER4 Compatible 40G ER4 QSFP+ Transceiver SMF 1310nm 40km LC DOM
Cisco®QSFP-40G-ER4 Compatible 40G ER4 QSFP+ Transceiver SMF 1310nm 40km LC DOM

Cisco®QSFP-40G-ER4 Compatible 40G ER4 QSFP+ Transceiver SMF 1310nm 40km LC DOM




Product Highlights


4 CWDM lanes MUX/DEMUX design


Hot-pluggable QSFP+ form factor


Transmission data rate up to 11.3Gbps per channel


Up to 40km transmission


SMF LC duplex connector


RoHS compliant

New Products

This 40GBASE-ER4 QSFP+ transceiver is compatible with Cisco 40G equipment and equivalent to genuine QSFP-40G-ER4. It is programmed and tested to work with Cisco 40 Gigabit Ethernet (GbE) switches and routers. It is designed for 40G Ethernet and high-performance computing networks application. It provides an ideal replacement to OEM transceiver at far less price. This QSFP-40G-ER4 replacement contains a LC Duplex connector for the optical interface and a 38-pin connector for the electrical interface.


Technical Specification

Compatible OEM Cisco® Compatible With OEM Part Number(s) QSFP-40G-ER4
Transceiver Type ER4  Reach 40km
Wavelength 1310nm CWDM4 Form Type QSFP+
Speed Description 40-Gigabit Media SMF
Connector LC  Extinction Ratio >5.5dB
TX Power -2.7~4.5dBm Receiver Sensitivity <-21dBm

40GBASE-ER4 Ethernet Switch, router and HBAs

Data Center Interconnect

Infiniband QDR

40G Campus Link


Operating:0°C to 70°C

Storage: -40°C to 85°C



Cisco  network switches • Cisco  network routers
Cisco  firewalls • Cisco  security gateway
• Cisco  fiber media converter • Cisco  network adapters
• Cisco  network interface card (NICs)
• Cisco  NAS

Quality Assurance



Quality Certification

FIBERTOP has strict control over all products' quality, including strict qualification audit for material suppliers, comprehensive quality management system and production process control which comply with the certifications and safety standard. Our products accord with industry standard and mainstream quality certification, such as  ISO 9001, CE, RoHS, CE, REACH, FCC, FDA, CB, UL etc.


  • Excellent quality is the foundation of FIBERTOP' s survival and development.
  • Our R&D team are experts with rich  experience in telecom industry.
  • Our material suppliers are first-class manufacturers in the industry.
  • We have the qualification of OEM for first-class system equipment manufacturers.







FIBERTOP provides after-sales service in strict accordance with Chinese Consumer Protection Law & Product Quality Law of the People's Republic of China. The defects liability period is provided for each product based on the materials, workmanship, frequency of use and service life. The return, replacement and repair services are as follows:




Return within 30 days


 replacement up to 1 year


Up to 5 years warranty

  • Warranty process

Provide relevant information(such as order number, product model, product serial number, product label, etc.)→Describe the problems you meet with→FIBERTOPSFP confirms that the product is complete and still in the warranty period→Send the product back to FIBERTOPSFP repair centre.

Note: The warranty peroid of the repair or replacement product is based on the longer time, either the remaining warranty period of the original product or ninety days after repair.


  • Request a Repair

When your FIBERTOP products need repairing (RMA-Return Material Authorization), please contact your sales consultant to provide timely service for you.


  • Free maintenance items

Guarantee repairing in two years:1. Not man made damage;  2. Product quality issues caused by design defects or material problems


  • The following conditions will not be repaired

• Maintenance center judge as non FIBERTOP products;

The appearance of man-made damage;

End face damage caused by use;

Inapplicable items listed in the warranty statement.


  • Warranty description

FIBERTOP guarantees that all products are subject to strict quality control from raw material procurement to production process. According to the problems raised by customers, if it is confirmed that the defective products are caused by raw materials or production process, FIBERTOP will provide repair or replacement services for free;

The warranty terms do not cover any damage to the product caused by improper installation, accidental disasters, natural disasters, abuse, misuse, inadequate or excessive power supply, incorrect operation, poor environmental conditions, and any unauthorized disassembly, repair or modification;

The warranty also does not apply to second-hand or unauthorized resale of products;

The FIBERTOP warranty only guarantees that customers can enjoy repair and replacement services when they purchase defective or damaged products; FIBERTOP is not obligated to compensate or assume responsibility for module damage and repair needs caused by other equipment in use.

The warranty does not cover problems caused by third-party software or connected related devices, etc.

FIBERTOP always adheres to the concept of "focus, innovation and progress", and is committed to providing every user with reliable products and enthusiastic services.
    Net Weight
0.046kg Gross Weight (with package) 0.32kg


Package of 1~20 pieces
  Step 1 Step 2  
  Step 3 Step 4  
Package of 21~80 pieces
  Step 1 Step 2  
  Step 3 Step 4  
Package of 81~160 pieces or more
  Step 1 Step 2  
  Step 3 Step 4  





FIBERTOP has established long-term cooperation with major global logistics companies to provide distribution services to more than 200 countries and regions.


Receiving Region Logistics Type Timeliness
Hong Kong, Macao and Taiwan SF 1~2 days
FedEx IP 1~3 days
FedEx IE 4~6 days
DHL 2~5 days
Overseas Regions UPS 1~3 days
FedEx 1~3 days
DHL 2~5 days



Note: 1. Timeliness is the estimated delivery time, some remote areas delivery may be delayed, the specific delivery time shall prevail;


  2. If you need to specify a logistics company, please contact  customer service staff or your sales representative.






FIBERTOP has 10+ years of R&D technology experience and more than 100 successful cases. With rich experience and R&D strength, we have a complete set of  services from the core system design to the compatibility design of SFP transceivers and  the completion of the final product,  we  can definitely satisfy our customers' needs through providing  customized high-performance products and solutions at the first time.


Product customization



















Scheme Customization













FIBERTOP focuses on customer-oriented solutions and provides technical support.


We can optimize the design based on your original solution, and also provide you with a complete network  solution, related products and technical support.





Cisco® Compatible 40G QSFP+ 100m~40km Transceivers

QSFP-40G-SR4 40G SR4 QSFP+ Transceiver MMF 850nm 100m MPO DOM 0-70℃
QSFP-40G-CSR4 40G QSFP+ Transceiver MMF 850nm 300m MPO DOM 0-70℃
QSFP-40G-LR4 40G LR4 QSFP+ Transceiver SMF 1310nm 10km LC DOM 0-70℃
QSFP-40G-ER4 40G ER4 QSFP+ Transceiver SMF 1310nm 40km LC DOM 0-70℃





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