Delphi Gateway Systems Analysis INterface Tool (SAINT), RS-232 Transmitted Keyword 2000 Messages

SAINT

Keyword 2000 to RS-232 Gateway

01/20/04

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4.4.2Transmitted Keyword 2000 Messages

The following is the format for sending a Keyword 2000 message:

Header	SID (Service Identification Byte)	N Data Bytes
28h	Byte 2	Bytes 3 ¾ (2+N)

The above information is used to form the following message which is sent onto the Keyword 2000 bus (with Length Byte not included in the Format Byte):

Format	Target	Source	Length	SID	N Data Bytes	Checksum
Byte 1	Byte2	Byte 3	Byte 4	Byte 5	Bytes 6 ¾ (5+N)	Byte (6+N)

The above information is used to form the following message which is sent onto the Keyword 2000 bus (with Length Byte included in the Format Byte):

Format	Target	Source	SID	N Data Bytes	Checksum
Byte 1	Byte2	Byte 3	Byte 4	Bytes 5 ¾ (6+N)	Byte (5+N)

Also, the SAINT will check to see if the bus is “initialized” and if necessary will send the Fast initialization sequence (transmit Wakeup Pattern of 25msec logic low and 25msec logic high followed by a Start Communications request message 81 11 F1 81 04). Refer to the “Keyword Protocol 2000 Data Link Layer Recommended Practice” section 5.1.5.3 for more information.

Currently, only the Fast Initialization sequence is supported. Future initialization sequences will be added as needed.