2. Compatibility. Optical modules usually need to be written in vendor information---compatibility. If the communication is not normal, make sure whether your optical module is compatible with the device.

3. Label. Although the label is small, it exhibit the brand of one company, and contains the basic information of a product. It is an integral part of the product. According to the Logo, ETU-Link provides company Logo、customer Logo、neutral label and blank label.

4. Test report. May be some customers will need test reports, according to it to analysis, to provide the basis for correcting the product quality problems.

To ensure stability, we need to pay attention to the followings:
1. Selection of patch cord
There are many types of patch cords, LC, SC, ST and FC etc., also single mode and multimode. Optical modules use with patch cord, if patch cord is not correct, it will affect the use of optical modules.

2. Port configuration
If communication is not properly, we need to do the following configuration, take H3C 5024P as an example. Now some commonly used switch ports is photoelectric multiplexing, most optical ports were still closed, need us to open the port.

For the communication between different brands of switches, we need to configure the port rate and operation mode to 1000Mpbs and full duplex mode

3. Cleaning of end face
End face should be clean, prevent dust from entering. Otherwise, the long-term accumulation of dirt will block the optical port, affecting transmission and stability.

All in all, the sample test is very important, the adoption of the sample is a prerequisite for large orders. So, we must not ignore the importance of sample testing.