| 摘要 |
PURPOSE:To secure standardization of the data format and thus to increase the transmission efficiency by including the code showing the presence or absence of the status and the text in the control field for HDLC. CONSTITUTION:The 8-bit structure following address field A is given to command character C or response character R of the control field. And 3 bits among the 8 bits are put under the idle state. Bits b1-b3 form status signal STS; bit b4 forms signal POL/INH showing the adaptablity of the polling or reception; and bit b5 forms signal T x T showing the presence or absence of the text respectively. Thus, the slave station decides the presence or absence of the information field by signal T x T, and sends signal STS back directly to the master station. |
