Dell 5535dn Mono Laser MFP - Manual (Page 66)

2 Connect one telephone cord into the LINE port of the printer, and then plug it into an active telephone wall
jack.
3 Remove the protective plug from the EXT port of the printer.
4 Connect a second telephone cord from the telephone to the answering machine.
5 Connect a third telephone cord from the answering machine to the EXT port of the printer.
Additional printer setup
66