Main function of OLT is to control the information float across the optical distribution network (ODN), going both directions
OLT has two float directions: upstream (getting an distributing different type of data and voice traffic from users) and downstream (getting data, voice and video traffic from metro network or from a long-haul network and send it to all ONT modules on the ODN.
Maximum distance supported for transmitting across the ODN is 20 km.