To communicate with the EPOS2 boards over CAN bus we use the ARM mbed microcontroller board.
You will find our repository for master and slave boards here : http://developer.mbed.org/users/therobotstudio/
Just compile the two projects and upload it to the corresponding master/slave mbeds on the robot.
Read this once you have your ROS nodes running :
On the master board, all the 4 leds will blink at the speed of the ROS heartbeat. It’s the same for the led0 on the slave boards. On these boards, led3 will blink when a command is being played, and led1 will stay on solid when an error frame is detected on the CAN bus.