■RS-232C Communication Protocol
The following pages detail the elements for communication between the Digital Disk Recorder and the personal computer. Be sure to select
1. Transmission Command
The PC sends messages to the Recorder in the format shown below. Also refer to the command table shown later.
Code | [STX] [Transmission Command] : [p1] : [p2] : | : [pn] [ETX] |
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ASCII | (02H) ( ) – – – – – – – – – – – – – – – – – ( | ) (03H) |
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[p]stands for parameter. Parameters are omitted when there is no need to specify them in the command.
2.Response Command
The Recorder returns messages in reply to the PC’s messages with the following formats.
(1)Reception Command
When the reception was completed successfully, the Recorder sends back the "ACK code 06H" to the PC, and then the response command below.
Code | [STX] [Response Command] : [p1] : [p2] : | : [pn] [ETX] |
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ASCII | (02H) ( ) – – – – – – – – – – – – – – – ( | ) (03H) |
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Parameters are omitted when the command format includes neither data nor status to send back.
(2)Reception error
The recorder sends back the "NAK code 15H", followed by the parameters shown below. The Recorder then resets the reception buffer and enters waiting mode for the next message. Parameter "e" identifies the error status.
Code | [NAK] [e] |
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ASCII | (15H) |
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"e" value | 1: Parity error (31H) | |
| 2: Framing error (33H) | |
| 3: Overrun error (34H) |
(3)Parameter error
The Recorder returns the "ACK code 06H", if the transmission code was not processed properly for some reason, followed by an error code as shown below.
Code | [STX] | ERE | [ETX] |
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ASCII | (02H) | (45H) | (03H) |
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Note: The Recorder returns [ACK] or [NAK] to the PC within 20 ms after the reception of [ETX] in a transmission.
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