Hello, everyone!
Today, I will start to write about ONU service interfaces. In these articles about ONU service interfaces, I will talk about basic information about interfaces such as ethernet ports, WiFi, POTS and RF. Today's topic is ethernet interfaces.
Ethernet interfaces are the most common type of interface on an ONU device. This type of interface can offer a GE or FE interface. The number of interfaces can be from 1 to 4, depending on the ONT model. At ONU, the number of ethernet ports can be higher than ONT.
UTP cables are used to connect devices (PCs, routers, ...) to the ONU. There are a large number of different UTP cables - UTP categories. These categories define transmission frequency, maximum cable length and transmission bandwidth. In the next table, we can see types of UTP cables.
Table 1. Types of UTP cables
To enable over GE interface internet speeds over 100 Mbps we need to use UTP cables min cat 5e. The maximum distance for a UTP cable is 100 m.
The connectors for UTP cables are 8-pin connectors – RJ45. Two standards are used to connect the device: T568A and T568B. Standard T568A or straight-thru UTP cable is used for connecting ONU and PCs or routers. But for connecting two PCs without ONU, router, or switch, we have to use T568B standard – crossover UTP cables.
Some ONU devices support PoE (IEEE 802.3). This technology allows remote power supply of the device via UTP cable. In addition to data transmission, the UTP cable uses two pairs to power the device. UTP cable min category 5e is used, and the voltage is 48 V. There are three standards: 802.3af, 802.3at, and 802.3bt.
Table 2. T568A and T568B
We can check the status of the PoE port on the ONT with the next command:
TEST(config-if-gpon-0/2)#display ont port poe 0 0 eth 1 ------------------------------------------------------------------------ Switch : Disable Force power switch : Disable Mode : Signal Priority : High Max power class : Class4 Capability : Capable Powered device class : Undefined Power supply status : No need to supply power Signal error count : 0 Power denied count : 0 Power overload count : 0 Current overload count : 0 Powered device undetected count : 0
This is the end of ethernet interfaces on the ONU. For more information about UTP cables, you can see the next link >> UTP cables.
I will continue this theme about ONU service interfaces in the next article >> ONU service interfaces (2): WiFi.
Thank you!
