When you go to setup a WPS Wi-FiWiFi connection the printer should tell you the PIN to use via its LCD.
See page 20 of the Brother Brother Network User’sNetwork User's Guide; “Using"Using the PIN method of Wi-Fi Protected Setup”Setup":
- Press “Menu"Menu".”
- Navigate to and select “Network"Network".”
- Navigate to and select “WLAN"WLAN".”
- Navigate to and select “WPS"WPS w/PIN CodeCode".”
- When “network"network I/F switched to Wireless”Wireless" is displayed, press “OK"OK".”
- The LCD will show an 8 digit PIN and the machine will begin to start searching for a WLAN access point/router for up to 5 minutes.