ICS ELECTRONICS 4863 Manual page 15

An acknowledgment packet is:
ACK Addr ESR_Register_Value ETX Checksum
1
ACK Addr Query_response ETX Checksum
An NAK packet is:
NAK Addr ESR_Register_Value ETX Checksum
Where:
ASCII characters 0 to 1F hex are reserved for message control.
ASCII characters 20-7F are for address and data.
Address character is 30-3F hex.
STX is ASCII character 02 hex.
ETX is ASCII character 03 hex.
ACK is ASCII character 06 hex.
NAK is ASCII character 15 hex.
Checksum is the exclusive OR sum of all of the characters
from the STX character though the ETX character.
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