Chapter 3. Communications Operations of the BHT
[ 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
Shown below is an example of a transmission message formed with the
Heading
Text text
Data text 1
Data text 2
Data text n
Transmission
Message
D | S |
| I | Heading text | D |
| E | C | Transmission | |
L | • O |
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E | H |
| D |
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| X | C |
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D | S |
| I | Serial |
| D |
| E | C | Transmission |
L | • T |
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| number | Data text 1 | L | • | T | R | |
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| block | ||||||||
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E | X |
| D | (5 bytes) |
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| X | C |
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D | S | I | Serial | Data text n | D | E | C | Transmission |
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L • | T |
| number | L • | T | R | ||
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| block | ||||||
E | X | D |
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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
You can use the control characters for expressing IDs, serial numbers, or text data.
