News Center

Why does the CAN bus have two 120Ω termination resistors ?

Why does the CAN bus have two 120Ω termination resistors  ?



Both ends of the CAN bus must be connected to a terminal resistor to work properly. 


The terminal resistor should be the same as the impedance of the communication cable, and the typical value is 120 ohms. 


Its function is to match the bus impedance and improve the anti-interference and reliable performance of data communication.


The function of the terminating resistor is to absorb signal reflection and echo, and if the impedance is discontinuous and mismatched, signal reflection will occur, which will interfere with the transmitted signal.


If the terminal resistance is added to two separate lines, it is equivalent to an open loop state. This type of connection results in a more discontinuous impedance on the single wire, suddenly going to 0 at the end, causing the reflection to multiply.


The two 120 ohm resistors added by the high-speed CAN actually simulate the characteristic impedance generated on the transmission line when the wire harness is connected to infinity, not the actual impedance. 


This is a typical empirical value, and the specific value depends on the type of wire harness used. .


The reason why high-speed CAN needs to add a terminal resistance is that when high-frequency signals are transmitted, the signal wavelength is shorter than that of the transmission line, and the signal will form a reflected wave at the end of the transmission line, which will interfere with the original signal. 


Therefore, it is necessary to add a terminal resistance at the end of the transmission line to make the signal reach the transmission line. Does not reflect after the end.


The reason why the low-speed CAN does not add terminating resistance is that the wavelength is relatively long and the reflection and echo are weak. 


However, the control unit of the low-speed CAN system will have its own independent terminal resistance, which is not connected between the CAN-high wire and the CAN-low wire, but between each wire and the ground or +5V power supply


Premier Cable CO LTD, , is a cable factory based in China, we mainly make CAN Termination resistors, plugs and cables , IOT related cables


Our cable and adapters are fully 100% compatible with PEAK-System ,  IXXAT , Kvaser , HMS, CSS Electronics


We make : 


CAN-T Adapter

CAN Bus Cable 

CAN Lin Cable 

CAN Adapter Cable

Null modem crossover cable

DB9 to 9-Pin Terminal Block Adapter 

D-sub 9 pin 120 Ohm termination adapter

CAN Termination resistors, plugs and cables



Welcome to your inquiry

Skype : james198585 


Email :

Email : 


CAN bus terminal resistor High-speed CAN 120 ohm resistor  Low-speed CAN terminal resistance CAN bus 120Ω termination resistor

Related News

What Cable Does Cisco Switch Console Use?

Which cable is required to establish a console connection from the computer to the Cisco router?You can find more Cisco Console Cables for video conferencing cameras, switches, routers, servers, firewalls, and other devices in Premier Cable.

What Does RET Cable Stand For?

Are you looking for an AISG RET Cable suppliers? Our Premier Cable is a cable harnesses manufacturer for Communication, Telecom, Base Stations, 5G Towers, IoT, Gateway. Leave us messages now to customized your needs.

What is the IX Industrial Ethernet Cable?

IX Industrial Ethernet Cable, the new transformation of Cat6a network cables. Our Premier Cable manufacture and export high-quality products of cable assemblies for medical devices, machine vision cameras, factory automation, robotics, PoE (Power over Ethernet), and industrial switches.

Is Servo Motor and Servo the Same Thing?

With the development of industrial automation and IoT, Servo Motor plays an important part. Our Premier Cable provides the Servo Motor Encoder Control Cable for robotics, smart networked vehicles, medical, textile, 3C, industrial automation, smart factories, IoT, AGV, and so on.

What does a NMEA 2000 do?

Are you looking for the NMEA 2000 Supplier? Our Premier Cable designs and manufactures cable assembly connectors that support open standard cables, cable assemblies, connectors, terminals, and power supplies for NMEA 2000 systems.

USB FTDI Cable IP67 waterproof round connector manufacturers introduce the development direction of the waterproof connector

USB FTDI Cable IP67 waterproof round connector Manufacturers tell you that the waterproof connector is a connector with the ability to work underwater, which can provide normal, safe, and reliable power supply and signal transmission to the electronic components, and can also play a very good role in the waterproof and dustproof effect.