Delphi Gateway Systems Analysis INterface Tool (SAINT) User Manual

 

4.4.5 

Target address byte 

This is the target address for the message and is always used together with the source address byte.  Refer to the 
“Keyword Protocol 2000 Data Link Layer Recommended Practice” section 4.1.2 for more information. 

4.4.6 

Source address byte 

This is the address of the transmitting device which is a physical address.  Refer to the “Keyword Protocol 2000 
Data Link Layer Recommended Practice” section 4.1.3 for more information. 

4.4.7 

Length byte 

This byte is provided if the length in the header byte (bits 0-5) is set to 0.  It allows the user to transmit messages 
with data fields longer than 63 bytes.  With shorter messages it may be omitted.  This byte defines the length of a 
message from the beginning of the data field (SID included) to the checksum byte (not included).  Refer to the 
“Keyword Protocol 2000 Data Link Layer Recommended Practice” section 4.1.4 for more information. 

4.4.8 

Data bytes 

The data field may contain up to 255 bytes.  The first byte of the data field is the Service Identification Byte.  Refer 
to the “Keyword Protocol 2000 Data Link Layer Recommended Practice” section 4.2 for more information. 

4.4.9 

Checksum byte 

The checksum byte inserted at the end of the message block is defined as the simple 8-bit sum series of all bytes in 
the message, excluding the checksum.  Refer to the “Keyword Protocol 2000 Data Link Layer Recommended 
Practice” section 4.3 for more information.