Closed Network RX is a function that restricts fax senders by passwords.
When receiving a fax, the machine checks the password sent from the sender against the password preset for this machine and, if they match, accepts transmission. Restricting fax senders helps to reduce unnecessary printing and wasteful paper use.
Enable the Closed Network RX function. Specify the password to restrict the communication.
For details on how to configure the settings, refer to Here.