Users need to convert QSFP ports to SFP ports for use. In addition to using QSFP branch cables (DAC or AOC) or MTP/MPO to LC jumpers, they can also use CVR-QSFP-SFP products, namely QSFP to SFP adapters, abbreviated as QSA modules.
1. Product Description
         The QSFP to SFP adapter has a QSFP package with an internal SFP module slot, which enables devices with QSFP interfaces to seamlessly connect with SFP interface devices. By inserting the SFP module into the QSFP to SFP adapter and then connecting the adapter to the device QSFP interface, 40G-10G connection or even 100G-25G connection can be realized. The QSFP to SFP adapter acts as an interface for the SFP module in the link.
Figure 1 Schematic diagram of QSA module
The 10G/25G SFP optical module is connected to the CVR-QSFP-SFP product, the optical module is connected to the patch cord, and the CVR-QSFP-SFP product is connected to the switch QSFP interface.
Figure 2 SFP module access QSA module schematic diagram
2. Module identification
         This test to H3C S6820-56HF switch as an example, were tested 10G LR module access CVR-QSFP-SFP products QSFP + 40G to SFP + 10G rate, as well as 25G SR access CVR-QSFP-SFP products QSFP28 100G to SFP28 25G rate. First of all, you need to configure the QSFP interface as a one-part-four mode, i.e., 4x10G or 4x25G. connect the CVR-QSFP-SFP product with the SFP optical module to the configured QSFP interface.
         The SFP module can LINK normally, and the port indicator lights up; the module information can be recognized normally by the switch, such as the module type, model, vendor name, wavelength, transmission distance, etc.; the DOM data can be read, and the DOM data are all within the threshold range, and there is no alarm phenomenon.
Table 1 Upstream identification of SFP module accessing QSA module
Item
 QSFP+ 40G to SFP+ 10G rate 
QSFP28 100G to SFP28 25G rate
Configuration
LINK

Identify 

DOM Data
         Note: Depending on the switch's compatibility with QSFP to SFP adapters, the optical module recognition varies and there may be cases where the SFP module type cannot be recognized or the SFP module DOM data cannot be read correctly.
         Moduletek Limited can supply the above CVR-QSFP-SFP products.
         If you have any questions about the above content, you can contact us by Email : web@moduletek.com