This appears to be a cable used to connect devices with an RS232C serial port (computers, modems, routers, etc.) to devices with an RJ45 port. It has a DB9 (D-sub 9-pin) female connector and an RJ45 male connector, and is primarily used as a console cable or configuration cable. The cable length is 2.5m. 【Important!!】Please confirm the following: About 15 years ago, I tried to introduce a Linux server and build a home network, but was rejected by my family in an instant and gave up. This is one of the items I purchased used at that time. I have never used it since I bought it, so the operation is unconfirmed. Since it has been stored for a long time, it may have deteriorated and become unusable, so I cannot guarantee its operation. Also, there are small scratches and dirt overall. Please purchase only if you agree with the above. Instant purchase OK. Thank you for viewing.