OLT: indicates an optical line terminal that is connected to an optical fiber trunk.

ONU: indicates an optical network unit. The ONU is divided into active optical network units and passive optical network units.

A PASSIVE OPTICAL NETWORK consists OF AN OPTICAL LINE TERMINAL (OLT) INSTALLED AT a CENTRAL CONTROL STATION AND a set OF SUPPORTING OPTICAL NETWORK UNITS (ONUs) installed at THE USER's SITE.

A device equipped with an optical receiver, an uplink optical transmitter, and a network monitor of multiple bridge amplifiers is called an optical node.

The PON uses a single fiber to connect to the OLT, which is then connected to the ONU. The ONU provides data, IPTV (interactive network TV), voice (Integrated Access Device) and other services to truly realize triple-play applications.

Differences between olt and onu:

Both OLT and ONU are part of the PON architecture. OLT is an optical line terminal and a local equipment of telecommunications, which is usually directly connected under BRAS.

An ONU is an optical network unit. Multiple ONUs can be attached to an OLT through an optical splitter. When an ONU is placed in a user's home, it is called fiber to the home (FTTH), and when it is placed in a building, it is called light to the building (FTTB).

There is no difference between ONU and PON. ONU is a device and PON is a technology or architecture.

An OLT is an optical line terminal and an ONU is an optical network unit (ONU). Both of them are connected devices in an optical transmission network. Passive Optical Network (PON) : Passive optical network (PON) PON (passive optical network) refers to (optical distribution network) does not contain any electronic devices and electronic power supply, ODN is composed of optical splitters and other passive devices, does not need valuable active electronic equipment. A PASSIVE OPTICAL NETWORK CONSISTS OF AN OPTICAL LINE TERMINAL (OLT) INSTALLED AT A CENTRAL CONTROL STATION AND a set OF ANCILLARY OPTICAL NETWORK UNITS (ONUs) INSTALLED AT THE USER's SITE. The optical wiring network (ODN) between the OLT and ONU consists of optical fibers and passive splitters or couplers.