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RS-232C specifications
(2) Sending format
(personal computer — VTR)
№ Data format
i
[STX]
[discrimination]
[:] [data]
02H
XX XX XX
ЗАН
xx
([;]
[discrimination]
[:] [data]...) [ETX]
3BH
XX XX XX
ЗАН
xx
03H
20H < xx < 7fH (xx = Hexadecimal character code)
°( )
The parentheses indicate that what is inside
them may be omitted.
e discrimination
This is the command identifier (3 bytes).
e:
This is a delimiter between command and data.
e data
A data code is added when so required.
1) A send command must start with STX (character
code 02H).
Discrimination,
which
follows,
identifies
the
command.
If necessary, data is added after the
colon.
The data must end with ETX (character
code 03H).
2) When
STX is re-sent before EXT is send, the
receive buffer inside the VTR is cleared (all data
received so far is lost), the re-received STX is
placed at the head, and the data is processed
anew.
(3) Receiving format
(VTR — personal computer)
The VTR responds to a send command with data in
the format below.
1) The response (return) data format used when
a command from the personal computer has
been
properly
received
by the VTR
is as
follow.
[STX]
[DATA] .... [ETX]
02H
XX
03H
example
:
Send command
Return data = receive data
[STX] ООР [ETX] — [STX] OEJ [ETX]
[STX] OPL [ETX] — [STX] OPL [ETX]
[STX] QCD [ETX] — [STX] CD 0000000000 [ЕТХ]
27
2)
When the data is incorrect or there is some
trouble with the VTR during reception, details
describing the reason why the data cannot be
received
are
returned
using the following
format.
[STX]
E
В
О [ETX]
(02H)
(45H)
(52H) (хх) (03H)
e Contents of D
D (44H):
This signifies that the processing by the
VTR has been disabled by condensation.
E (65H):
This data announces
that a command
which cannot be processed by the VTR
has been received.
One of the following causes may be to
blame for this.
@ An unsupported command
has been
received.
e The wrong data code is used.
e The data is outside the permitted range.
€.A command
was received in a mode
(playback during counter search, etc.)
in
which
commands
cannot
be
received.
In the case of a communication error, the VTR
returns data starting with NACK
(negative
. acknowledge character code 15H) when the
error is detected.
If the VTR is in the process
of
sending
data
when
it receives
the
communication, NACK is returned after the
sending of the data has been completed.
in
this case, the VTR destroys all the error data
which was received.
[NACK]
LJ
(15H)
(xx)
® Contents of [ ]
4 (34H) : Over Run Error
1 (31H):
Parity Error
3 (33H) : Framing Error
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