The latest update of the open source can2 protocol decoder is able to automatically infer the sender of a CAN frame. It uses the method of deterministic distortion of CAN signals that result in frames from a given node on the bus having consistently shortened or lengthened recessive pulses. The differences can be quite small - just 10 or 15 nanoseconds - but they can be picked up by a suitably accurate logic analyzer. A few years ago I developed the decoder to show much more information about...
