Canon LBP7780CX User Manual page 697

(1) Enter the MAC address of a device of which you want to permit to access.
Enter the address without placing a hyphen (-) between characters, like AABBCCDDEEFF.
(2) Click [Add].
You can set up to 50 addresses.
NOTE
When deleting a set MAC address
(1) Select a MAC address you want to delete.
(2) Click [Delete].