Terminal Resistor 120 Ohm CAN Bus DB9

Terminal Resistor (120 Ohm, DB9, CAN Bus)

Need a low cost CAN bus terminator for your high speed CAN bus application?

This CAN bus termination resistor is a D-sub 9 pin male connector & female socket. It contains a 120 Ohm terminal resistor between the CAN High / CAN Low pins.

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Regular price
25 EUR
Unit price
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120 Ohm Terminal Resistor

120 ohm terminal resistors are great for e.g. test setups

Compatible with CAN and CAN FD Flexible Data Rate

Supports regular high speed ISO 11898-2 CAN and CAN FD

Lock Cables with Screws

DB9 screw locks ensure a solid connection

Compact Small Tiny

The termination adapter is extremely compact

Standard CAN in Automation DB9

Works with most CAN adapters (CiA 303-1 compatible DB9 pins)

1 Year Warranty

We offer a 1-year warranty on all our products

About terminal resistors

A CAN bus terminator can be used for termination of any high speed (ISO 11898-2) CAN bus system. The 120 Ohm terminating resistor is setup between pin 2 (CAN low) and pin 7 (CAN high). In general, ISO 11898-2 CAN networks must be terminated at each end using 120 Ohm terminal resistors.

Terminal resistors are often required in test setups when CAN nodes have no existing termination. In contrast, most vehicle CAN buses are already terminated properly.

CAN Bus Terminal Resistor

120 Ohm Termination Adapter D Sub 9

What role does CAN bus termination play?

Terminal resistors are needed in CAN bus systems because CAN communication flows are two-way. The termination at each end absorbs the CAN signal energy, ensuring that this is not reflected from the cable ends. Such reflections would cause interference and potentially damaged signals.

The reflection challenge grows with the length of the cables as well as the CAN bus bit rate. This is why it is critical to add proper termination in larger CAN networks.

For best results, the CAN bus termination should match the nominal impedance of the cables, which for ISO 11898-2 (high speed CAN) is specified at 120 Ohm. Hence 120 Ohm termination adaptors are considered the standard for CAN bus.

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Compatibility High Speed CAN Bus (ISO 11898-2) incl. CAN FD, SAE J1939, OBD2, NMEA, CANopen
Connector Male / Female DB9 (D-sub 9 pin)
Temperature Operating temperature: -20degC to +80degC
Pin-out In accordance with CiA 303-1 (matching our other devices/accessories)

Adapter pinout

DB9 (female) Function DB9 (male)
1 1
2 120 ohm to pin 7 2
3 3
4 5
5 5
6 6
7 120 ohm to pin 2 7
8 8
9 9

Not necessarily. For very small CAN wire systems, you can typically do with just a single 120 Ohm termination adaptor. This is sometimes seen in e.g. test setups with one or a few CAN nodes. Note, however, that you cannot do without a termination adaptor in high speed (ISO 11898-2) CAN bus systems.

For larger CAN bus systems, you'll quickly run into "reflection" issues, while on short CAN bus cables you may not notice in practice any difference. Either way, it is strongly recommended to use 2 x 120 Ohm terminal resistors for larger CAN bus systems.

You can encounter "reflections", which in practical terms can lead to damaged data and hence incorrect interpretation of your output - or worse, inadequate reactions from vital CAN nodes in the system

Not if you use two 120 Ohm CAN bus terminators, one at each end. This assures a 60 Ohm load, which will secure the adequate recessive level regardless of the number of CAN nodes.

Yes, the CAN bus terminator can be used in any high speed CAN bus application, including applications based on J1939, CANopen, FMS, NMEA 2000 etc.

Yes, you can measure the resistance between the CAN High and CAN Low when the CAN bus system is powered down. If properly terminated at both ends, the resistance should be around 60 Ohm.