What is OLT?

OLT stands for Optical Line Terminal. An OLT is an optical line terminal and an office device of telecommunications. It is used to connect to the optical fiber trunk and functions as a switch or router in a traditional communication network. It is a device that connects the external network to the internal network. Placed at the office end, the most important executive functions are traffic scheduling, buffer control, and the provision of user-facing passive fiber network interfaces and bandwidth allocation. To put it simply, it is to achieve two functions: upstream, to complete the upstream access of PON network; Downstream, the obtained data is sent to all ONU user terminal devices through the ODN network.

What is an ONU?

An ONU is an Optical Network Unit. ONU has two functions: to selectively receive the broadcast sent by OLT, and to receive the response to the OLT if the data needs to be received; Collect and cache Ethernet data that users need to send, and send the cached data to the OLT end according to the assigned sending window.

For example, Fiber To The Curb (FTTC) : The ONU is placed in the center room of the community. FTTB(Fiber To The Building) : ONU is placed in the terminal box of the corridor; FTTH(Fiber To The Home) : The ONU is placed in the home user.

What is ONT?

ONT is the Optical Network Terminal, the terminal unit of FTTH, commonly known as "light cat", similar to xDSL's electric cat. An ONT is an optical network terminal, applied to the end user, while an ONU is an optical network unit, and there may be other networks between it and the end user. ONT is an integral part of ONU.

What is the relationship between ONU and OLT?

OLT is the management terminal and ONU is the terminal. The service commissioning of ONU is delivered through OLT, and the relationship between the two is master-slave. Multiple ONUs can be attached to one OLT through the splitter.

What is ODN?

ODN is an Optical Distribution Network and an optical distribution network. It is a physical optical transmission channel between OLT and ONU, and its main function is to complete the bidirectional transmission of optical signals. It is usually composed of optical fiber and cable, optical connector, optical splitter, and supporting equipment for installing and connecting these devices. One of the most important components is the optical splitter.