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Note: I am not talking about connecting an RS-232 device to a CAN bus!

I am strictly interested in reusing a RS-232 cable with two DB-9 connectors (one male and one female) to connect two CAN devices, each having a single DB-9 port (one female and one male).

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    \$\begingroup\$ It depends on what pins the CAN bus uses and if the cable even wires them. We don't know what pins you need and does your cable connect the pins or not. But one thing is sure, even if the cable does connect the pins, it's just a standard cable, it won't be a 120 ohm differential pair. Please add the relevant info to answer your question. \$\endgroup\$
    – Justme
    Commented Apr 17, 2023 at 8:16
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    \$\begingroup\$ Don't buy a "RS-232 cable", but a DB9F to DB9M cable. As always with cables, length matters. \$\endgroup\$
    – Lundin
    Commented Apr 17, 2023 at 8:26
  • \$\begingroup\$ When in doubt, ohm it out! Make sure you have conductors for the pins that hook up to CAN+ and CAN- pins, which is not quite a standard. I've seen at least 2 different configurations for pinning of CAN+ and CAN-. Also, as @Justme says, make sure the devices on each end have the 120 ohm terminations at both ends. \$\endgroup\$
    – RufusVS
    Commented May 10, 2023 at 20:04
  • \$\begingroup\$ @RufusVS I didn't say that. I said it needs to be a transmission line with 120 ohm differential impedance, which is not the same as having 120 ohm terminations at each end. \$\endgroup\$
    – Justme
    Commented May 10, 2023 at 20:35

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