Having just poked my nose into the thread about transient protection on
CANbus systems I opened my (snail) mail to find a Maxim notification about
+/-80V protected CAN transceivers designed for 42V automotive systems. Check
out the MAX305x family. Sounds like the sort of device to use for an HA bus
for transient protection. They appear to be pin compatible to other 8 pin
devices, although I think pin 5 changes function slightly.

They also have RS485 versions as the MAX343x/344x families.

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