Dell OptiPlex 755 - Manual (Page 52)

12. Type the port in the Port number field and press <Enter>. The default setting is 0. If left at the default setting of 0, the Intel AMT attempts to contact
the provisioning server on port 9971. If the provisioning server is listening on a different port, enter it here.
13. Select TLS PSK from the menu. Press <Enter>.