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Communication
13-3 Communication format
The communication formats of the commands and responses between the IV-S20 and a personal
computer are outlined below.
Ë Command
Ë Response
*1 Processing code and text
- They depend on the contents of communication. (See pages 13-1 and 13-6 and after.)
- On abnormal termination, no text is provided.
*2 Termination code
The termination code is a 2-digit hexadecimal number.
- When an output is sent through the general purpose serial I/F, 00
- On abnormal termination, a code other than 00
*3 Checksum code (SC
To improve the reliability of the transmitted data, in addition to a parity check, error detection
by a checksum is used for error detection.
When the IV-S20 does not need to complete a checksum for error detection, use an @ (at
sign: ASCII code 40
[Error detection using a checksum]
The ASCII code for each data byte, from the processing code to the end of text (prior to the
checksum code), is added. The final value is compared to the checksum code which is
treated the same way. If the two values are identical, the command is considered to be
valid. I/F they are not identical, an error has occurred during transmission.
13
Ë
Command
Ë
Response
:
*1
Processing
code
RC
RC
:
H
L
*2
Termination
code
*1
Processing
code
nation.
and SC
H
) in each of the checksum codes SC
(H)
Value increment range for
checksum
:
Processing
code
Value increment range for
RC
RC
:
H
L
Termination
code
Processing
code
SC
SC
CR
...............
H
L
*3
*1
Text
Checksum code
SC
SC
...............
H
*1
Text
is sent. (See page 15-3.)
(H)
)
L
SC
CR
SC
H
L
Text
Checksum code
checksum
SC
H
Text
13-4
Terminator
CR
L
Terminator
*3
Checksum code
is sent on normal termi-
(H)
and SC
included in the command.
H
L
Terminator
SC
CR
L
Terminator
Checksum code
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