Answer: The quotation is valid for 15 days. If it exceeds the expiration date, you need to confirm with your account manager if there are any changes.

Answer: Of course, many of our products are not listed on the website. You can contact our customer service team or your account manager to confirm.

Answer: You can submit an application through our official website, and your account manager will follow up on your request.

Answer: You can submit an application through the sample request form on our official website, and your account manager will follow up on your request.

Answer: All products provided by BeiYang undergo comprehensive testing before shipping. For compatibility of optical modules, 

you can visit our optical module testing to see how we perform compatibility testing. 

If you have any other questions, you can ask for assistance in customer support.