Configuration Guide: P-3521 MFP | P-3527w MFP | P-4020 MFP | P-4025w MFP | P-4026iw MFP
Please use the UTAX (UK) Ltd version which details all associated configuration options for the devices listed above.
Download Link: https://www.utax.co.uk/downloads/configuration-guides/p-3521-p-4026iw-mfp-configuration-guides/