The basics of PON, EPON & GPON

Fiber optic Internet is a high-speed broadband connection. Information is delivered across an optic fiber line using infrared light pulses.

There are a few words and abbreviations you should be familiar with in order to better understand fiber optics. Before we get into detail about each form of passive optical network (EPON, and GPON) here they are:

OLT (Optical Line Terminal)

Your Internet service provider's (ISP) equipment that operates as the endpoint of a PON and your ISP's core network is known as an OLT device. The purpose of an OLT in a PON system is to regulate, convert signals, and coordinate fiber optic service (FiOS).

ONT (Optical Network Terminal)

The endpoint at your location is an ONT device. The goal of an ONT is similar to that of a modem, however it is specific to fiber. Within a PON system, it communicates with your ISP via a fiber optical line.

ONU (Optical Network Unit) 

The terms ONT and ONU are frequently interchanged, and both are end-user devices.

Within a PON network, both OLT and ONT devices are required. They terminate at each end of the connection, one at your house or business (ONT/ONU) and the other at your ISP (OLT).

What is PON?

The term PON refers to a passive optical network. It is the network system that delivers broadband Internet access by carrying optical fiber cabling and communications from an ISP to the end user. A PON system can terminate in a variety of locations, including a subscriber's home, an office building, or a neighborhood "curb" or shared point. These terminations are described as follows:

• Fiber-to-the-premise (FTTP)
• Fiber-to-the-home (FTTH)
• Fiber-to-the-building (FTTB)
• Fiber-to-the-curb (FTTC)