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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 and terminator are
added to each block. If the serial number management or error checking by BCC (Block Check
Character) is required, the serial number or BCC is also added to each block, respectively. 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-protocol.
In the above figure, SOH, STX, and ETX are text control characters as described in [ 2 ] Control
Characters, (2). A serial number is expressed by a five-digit decimal number, starting from 00001 to
32767, and identifies transmitted data texts. For the BCC, refer to Appendix B, B.1, "BHT-protocol,"
[ 3 ].
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