Ricoh 4016 Series - Manual (Page 21)

G ETTING STARTED 1.10
Plug the cord of your extension phone or answering
machine into the EXT jack.
N OTE : You should use the telephone line cord which is supplied
with your machine. If you are replacing it with another vendor’s, it
should be AWG #26 or lower gage.
3 Connect the USB cable which came with your machine.