Chapter 3 Communications Operations of BHT
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[ 3 ] Basic Format of Transmission Messages
Basically, the BHT transmits data as units of a file. First, it transmits a heading text which includes the
attribute information of a file (e.g., file name and the number of data texts) to be transmitted. Following
the heading text, it transmits the data text in the file. A heading text and data text comprise a text.
In actual text transmission, the text is divided into several blocks, then a header, terminator, serial
number, receiver station's ID, and CRC-16 (Cyclic Redundancy Check) are added to each block. This
procedure forms a transmission block. A set of transmission blocks makes up one transmission
message.
Shown below is an example of a transmission message formed with the BHT-Ir protocol.
In the above figure, DLE SOH, DLE STX and DLE ETX are text control characters as described in [ 2 ]
Control Characters, (2). An ID denotes the ID number of the receiver station, expressed by two bytes. A
serial number is expressed by a five-digit decimal number, starting from 00001 to 32767, and identifies
data texts. For the CRC-16, refer to Appendix B, B.2, "BHT-Ir protocol, " [ 3 ].
You can use the control characters for expressing IDs, serial numbers, or text data.
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