Access it using a laptop or desktop computer with a serial cable. The cable should have a DB connector for the back of the computer and an RJ-45 connector at the other. The RJ-45 goes to the AUX port on the switch and the DB-9 goes to the PC.
If it is not the AUX port, it might be the COM port. I forget.
Use Hyperterm (hyperterminal), which is easily downloaded and free from many reputable shareware sites. Make a new connection, typically to COM1 and 9600, 8, n, 1 for the port settings.
If you don’t see a response on the port you tried, try the other. DO NOT use the Ethernet port if it can be identified.
When you have a physical connection with the PC and switch on, open Hyperterm. Open a connection and give the connection a name. With the connection open, hit Enter twice. If all is right, you will be presented with a prompt. Proceed from there.