Composition Rule of Character Codes to efficiently transmit the Character Code in HDLC(High-level Data Link Control) Protocol

Abstract

This paper is to show the character coding rule in computer and information equipment etc to improve the transmission efficiency in telecommunications. In the transmission system, the transmission efficiency can be increased by applying the proper character coding method. In datalink layer, HDSL ptotocol use FLAG byte to identify the frame to frame which consists of data bit stream and other control bytes. FLAG byte constits of 01111110. When data bit stream consist of the consecutive 5-bit 1 after 0, the decoder can not distinguish whether the data bit sequence is flag bit stream or data bit stream. To solve the problem, when the line coder in transmitter detects the consecutive 5-bits 1 after 0 in the input data stream, inserts violently the 0 after 5th 1 of the consecutive 5-bit 1 after 0. As a result, when the characters are decoded with the above procedure, the efficiency of system should be decreased. This paper shows the character code rule to minimize the consecutive 5-bits 1 after 0 when the code is given to each characters.