Hi Claudio, as already said by Ronald, the Pinout Assignments might be different among platforms.
For 800-Series you have the following:
An optional console cable (08A-CON-CBL) is required if you want to locally manage the switch via the front panel RJ45 console port. The cable is terminated by an RJ45 connector at one end and by a DB9 female connector at the other end. Using an RJ45-to-DB9 female cable, you can connect products equipped with a RJ45 console port to an IBM or compatible PC running a VT series emulation software package.
You can get this information in 800-Series Hardware Installation Guide.