The best replacement for can bus is rs485.

The best alternatives to can bus are rated as following:
★★★★★  rs485
★★★★  i2c
★★★★  lin bus
★★★  modbus
★★★  profibus
★★★  most bus
★★  obd2
★★  rs232
★  devicenet
★  arinc 429
★  low speed can bus
★  rs 485
★  obd
★  flexray
★  j1939
  k-line

Your alternative for can bus is not listed? Suggest!
Speaking about can bus, one probably shouldn't forget about microcontroller.

Other search terms related to can bus and their ratings are:
★★★★★ microcontroller
You have in mind a companion for can bus and it is not yet here? Propose!



Google Trends

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can bus
rs485
i2c