Rs232 Alarm/Event Generation/Text Insertion Protocol; Message Structure; Message Type - GE DVMRe CT II User Manual

8
RS232 Alarm/Event Generation/Text Insertion
Protocol
The RS232 Alarm/Event Generation /Text Insertion Protocol is designed to deliver Alarm, Event
(commands), and Text data to the DVMRe from serial interface devices through the RS232 port.
NOTE
Setting and Clearing Alarms with this Protocol is equivalent to activating and deactivating
Alarms on the hardware alarm inputs.

8.1 Message Structure

The Delimiter byte signals the start of a new message, and has a value of 0xFF.
The Class and Command fields identify the type of message.
The Data Length is a 16-bit value indicating the number of bytes in the Data portion of
the message. Data Length is sent using Intel byte ordering (Little Endian).
The Check Sum byte is the result of XORing all the bytes in the message.

8.2 Message Type

One message is currently supported to store text along with recorded video.
CMD_NEW_ADD_TEXT
Class byte is 0x14.
Command byte is 0x40.
Data Length is the number of data bytes in the message (from 2 to 502).
Camera byte indicates the camera associated with the alarm, event, or text. The
valid range is from 0 to 15.
Alarm/Event byte usage is described in the following section.
String fields contain text characters. The string length can be from 0 to 500
characters in length. The String field is not required. If text data is available, it will be
recorded with the next video frame for the camera identified by the camera field.
0150-0313B 88
Delimiter
Class
Command
Data Length
Data
Check Sum
0xFF
0x14
0x40
Data Length[0]
Data Length[1]
Camera
Alarm/Event
String[0]
String[1]
:
String[n-1]
Check Sum
DVMRe CT II