Delphi Gateway Systems Analysis INterface Tool (SAINT) manual Page 14 of, 4.4.5Target address byte

SAINT

Keyword 2000 to RS-232 Gateway

01/20/04

Page 14 of 20

4.4.5Target 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.

4.4.6Source 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.

4.4.7Length 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.

4.4.8Data 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.

4.4.9Checksum 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.