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I was wondering, can I connect the CAN H and CAN L terminals of a MCP2551 or SN65HVD230 transceiver to the 12V and GND to send signals to other devices that are connected the same way?

I always thought CAN was meant to be used over the DC wiring (I think it works like that in cars...?) but I have looked through the datasheets and cannot any reference to it...

Anybody have any experience/insights in this?

Thx, Jeroen

PS and suppose it can be used over 12V lines what to do with the terminator resistors (120 ohms), this would cause a continues power drain of ~100 mA at both terminated sides...

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    \$\begingroup\$ I always thought CAN was meant to be used over the DC wiring Do you mean you think that the wires are used for supplying DC power and CAN but data at the same time? They're not. The CAN bus wires are separate wires. \$\endgroup\$ – Bimpelrekkie 2 days ago
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    \$\begingroup\$ I think you're confusing what common mode tolerance is. It's not sending signal over power. \$\endgroup\$ – DKNguyen 2 days ago
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No, it must use a separate CAN bus wires, it can't communicate over 12V power supply wires.

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You already have a direct answer for the exact question in OP. I'd like to answer more broad question in the title, just for the sake of completion.

Yes, it is possible to have CAN network operate over 12V DC, just as it is possible to operate pretty much any wired protocol over AC or DC power lines, using PLC (Power-line communication) with suitable bandwidth and PHY adapters on both ends.

A typical DC example would be DC-LIN network which is approved ISO 17987-8 standard for in-vehicle communication. Since CAN can go up to 1Mbps (5Mbps for CAN-FD) you have to use BPL (Broadband over power lines) version of the PLC to get required transport bandwidth.

The caveat, however, is that BPL hardware is much more complicated than simple CAN transceiver. It typically requires broadband modem, analog front-end, line driver and line coupling circuit. This is only to establish physical layer of communication. To use it as underlying CAN transport you also need to add adapters in place of traditional transceivers.

In short, yes, it is possible but at impractical cost and certainly not with transceivers you've mentioned, as @Justme pointed out.

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