The end-of-frame consists of 7 recessive bits. It is often written that it is used to detect stuffing errors by a receiver. I also read that if the 7th bit is driven to dominant level, the transmitter is detecting this as an error? However, it was not written who puts the 7th bit to the dominant level.

I have two questions:

  1. Why can I detect stuffing errors with the end-of-frame?
  2. Is the 7th bit a NACK send bit the receivers if a stuffing error happens?