What is an ONU？

ONU, also known as Optical Network Unit, is a device that converts optical signals into electrical signals. The "optical" in its name refers to optical signals, which feature extremely high transmission speeds. ONU plays a crucial role in network connections: it receives optical signals from the optical fiber trunk line and converts them into electrical signals that can then be recognized by devices such as computers and routers.

In addition, ONU also performs the tasks of dial-up and user authentication. In some settings, ONU can be set to bridge mode, in which case the dial-up action can be completed by the router, while ONU is only responsible for optoelectronic conversion and data transmission and reception.

It's important to note that some service providers offer ONUs for rent, which users can use free of charge during the contract period and which include maintenance services. At the same time, modern ONUs often also have the functions of wired routing and even wireless routing, which means that under certain configurations, it is possible to access the Internet with only an ONU. However, if there is only a router and no ONU, it is impossible to connect to the Internet.

ONU vs. Router

ONU and router are two different devices that play their own roles in network connection.

First, ONU, also known as Optical Network Unit, is a device that converts optical signals into electrical signals. The "optical" in its name refers to optical signals, which feature extremely high transmission speeds. ONU plays a crucial role in network connections: it receives optical signals from the optical fiber trunk line and converts them into electrical signals that can then be recognized by devices such as computers and routers.

Next, a router is a network device whose main function is to connect multiple devices and enable them to share an Internet connection. The router forms an independent local area network through a switch device, can connect multiple devices, and provides wireless network services.

In general, ONU and router have their own functions. ONU is mainly responsible for signal conversion and access, while router is responsible for connection between devices and data transmission. It should be noted that although ONU and router operate independently, they usually need to be used together. In other words, you need an ONU to receive optical signals from the ISP and convert them into electrical signals, and then use a router to distribute these electrical signals to various devices in your home.

How to Choose an ONU?

You can judge the quality of an ONU from the following aspects:

Observe the indicator light: The status of the ONU's indicator light can provide some information about the quality of the device. Generally speaking, the Power light should be always on, and if it blinks, it may indicate a power abnormality. The PON light should be always on, and if it is off or blinking, it may indicate that the optical path is not smooth.

Network performance: Find the network attribute settings, check its specific attributes, find the connection speed column, which shows the current network speed. For example, current dual-band ONUs and ONUs with WIFI6 function have significantly improved performance and stability.

Understand the operator's positioning of the ONU: The operator's positioning of the ONU varies in different periods. In the early days, in order to reduce costs, the stability of ONUs was indeed generally poor. Now, many cities are equipped with dual-band ONUs, and their performance and stability have been significantly improved.

Extensibility: If you are worried that the performance of the ONU is insufficient and you do not insist on using only one ONU, then you can also purchase an optical fiber splitter and an optical fiber jumper, and divide a fiber entering the household into two or more ONUs for use.

In today's interconnected world, understanding your home network is crucial. While terms like "modem" and "router" get thrown around frequently, their distinctions might remain unclear. This article delves into the world of optical modems, explaining their function and how they differ from their network partner, the router.