Xicom XTU-400K, Operation And Installation Manual

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MNC-0500-002 10 of 36 Revision H
Amplifier Communication and Protocol, Octagon ISA CPU
Table 3, Start Byte, End Byte, & Check Byte
Protocol
Packet
Type
Accept/
Reject
Start Byte End Byte Check Byte
Printable Message (ASCII){ (ASCII)}
Response
Message
Accepted or
Rejected
{ } “Base 95”
Message STX ETX
Non-Printable
Response
Message
Accepted
ACK ETX “Exclusive OR”
Message
Rejected
NAK ETX
Table 4, Check Byte Calculation
“Base 95” 1. Take [Sum (all message bytes)] – 32 = C
2. Then take [Modulus C (“Base 95”)] + 32 = Result (Printable ASCII
character in range of 32 to 126)
“Exclusive OR” XOR (all message bytes) = Result (non-printable byte)