D-Link D DPH-50U DPH-50U Quick User Manual page 14

STEP 4:
Connect a standard telephone handset to the DPH-50U phone jack
using a telephone cable as shown below
STEP 5:
Connect a telephone cable between the DPH-50U line jack and a
wall jack as shown below. Note that this is only required for making regular
phone calls or for forwarding Skype calls to your mobile (or other off-site)
phone or for toll bypass applications.