Detailed practice is the sender when sending all information (except flag byte), as long as meet five consecutive "1", is automatically inserted into a "0" when the receiver receive data (except flag byte) if received five consecutive "1", automatically will be followed by a "0" to delete, to restore the original form of information, this kind of "0" bit insertion and deletion process is done automatically by the hardware, than the character-oriented "data transparency" easy to implement,

Example: composite station is sending command and response, also to receive from another in line with the standing orders and response,
13. In HDLC protocol from top receive block of 011111011110111111011111110 bits, try to write after filling in the data frame according to the bit stuffing algorithm corresponds to the bits in the block's output,
Fill the results as follows: after 0111, 11001111011111010111110110