Version 1 (modified by TonyB, 6 years ago) (diff)


Connecting CANOpen Equipment with DB9M Connectors to a RJ45 Network

DB9 Conversion Strategies

For normal environments, I like using RJ45 cables to connect my CANOpen equipment. If all CANOpen equipment had dual RJ45 jacks, connecting the devices together would be easy. Unfortunately, many devices aren't available with dual RJ45's. For example, older AMC servo drives use a single DB9M, the IMS MDrives use a single DB9M (Plus, Plus2) or M12 (Plus2-65), and most CAN interfaces use a single DB9M.

My approach is to convert all the other devices to use dual RJ45 jacks; for DB9M-equipped devices, that means using a DB9M/RJ45 Modular Adapter connected to a RJ duplex (tee) adapter. The advantage is now all the equipment has the same configuration: dual RJ45 jacks. So it's easy to put any device anywhere in the network. The first and last devices have RJ45 terminators.

If you have only one or two devices with DB9M connectors, then you don't need to use the RJ45 duplex adapters. You can use the DB9/RJ45 Modular Adapter with a DB9 pass through terminator such as this Ixxat model, which looks nice but is a little pricey at $25. For example, a system with a DB9 CAN interface, three Copley Accelnet Panel drives, and a IMS MDrive 17 Plus could be connected like this: DB9 CAN inteface DB9 is connected to the DB9 pass through terminator connected to a RJ45 modular adapter connected to RJ45 patch cable connected to Copley 1 connected to patch cable connected to Copley 2 connected to patch cable connected to Copley 3 connected to patch cable connected to RJ45/DB9 adapter connected to DB9 pass through terminator connected to the MDrive.

Using a DB9/RJ45 Modular Adapter

The simplest approach is to use a DB9 to Modular converter. The table below shows the required connections for the two adapters I've tried, a Norcomp RJADK09S7080831 from Mouser and a Pan Pacific ADM-9F8-GR from Fry's Electronics.

The Pan Pacific looks prettier, but I had to remove one of the thumbscrews because it interfered with the RJ45 duplex adapter.

Connections using Norcomp RJADK09S7080831 or Pan Pacific ADM-9F8 Modular Adapter -- Complete

DB9F PinCAN SignalRJ45 PinWire ColorCAN Signal
1ReservedNC Reserved
2CAN_L 2 OrangeCAN_L
4ReservedNC Reserved
6GND 7 Brown GND
7CAN_H 1 Blue CAN_H
8ReservedNC Reserved
9CAN_V+ 8 White CAN_V+
4 Red Reserved
5 Green Reserved

Easy Wiring Table for Norcomp RJADK09S7080831 or Pan Pacific ADM-9F8 Modular Adapter

Wire ColorDB9F PinCAN Signal


  1. If the modular adapter isn't a Norcomp RJADK09S7080831 or Pan Pacific ADM-9F8, then you need to determine which wires are connected to which pins.
    1. With the contacts on the bottom, RJ45 pin 1 is the contact on the far right.
  2. Carefully insert the crimped pins into the appropriate hole in the DB9F connector until they snap into place and won't come out. A small screw driver or insertion tool can help.
    1. Be careful - so far in my experience, removing DB crimp pins is a huge pain. If you don't have the proper tools, it's just about impossible. Even with the correct crimp pin removal tool, it is not easy -- don't expect your removal tool to last very long.
  3. Test the adapter in your CANOpen network.
  4. Once you've verifed it works, chop off the extra wires.
  5. Snap the DB9F connector into the backshell, pushing the the wires into the backshell.
  6. Test again
Pan Pacific DB9F to RJ45 Modular Adapter - configured for CANOpen
DB9/RJ45 Adapter with Modular Tee
For production, I would remove the release tab that you can see sticking out at the top.