Bit plug
When bit stuffing ( English bit stuffing ) is referred to in the communications engineering the insertion of one or more fill bits (i. E. Not in a data transmission to signal information useful data proper) to be transmitted to the receiver. In this case, the recipient must know how to recognize and remove these additional bits in order to receive the actual user data.
One possible example is the block structure in HDLC .
Bit stuffing with CAN
The procedure is also used with CAN . In order to enable synchronization of the participants, long monotonous sequences of 0 or 1 should be prevented from being transmitted. This is to prevent the transmission between transmitter and receiver from drifting apart (e.g. due to somewhat imprecise clock signals between the ICs or communication participants involved ).
With bit stuffing, an inverse bit is inserted after five identical bits (this interrupts a monotonous sequence). The receiver knows this procedure and removes the following sixth bit when it receives a sequence of five identical bits and thus receives the original data. The sixth bit can be examined as a further possibility: If it violates the rules of bit stuffing, a transmission error is detected.